 Alright friends, so welcome to your first session on physics for class 11th while you are in class 10th Okay, so just wanted to know first of all like how many of you were with the sentiment earlier and Like you were the sentiment student in class 10. So can you just message me? Who all were the sentiment students earlier? Okay, so Aiden, Aniket, Anirudh, Anirudh Vapattu, Anish Okay Surya Momita, okay, good. So Anybody else so we have a good number of students Okay, Aiden was also from class 9th. Okay, so you guys are pretty much aware of You know the basic processes we follow in the sentiment, but having said that Like quite a few of you are new today So we'll be covering up a little bit of basics of how We will work with respect to physics because I believe Akhil has given you a brief about the overall planner about various exams and how you should take up all those things So I'll be you know my discussion will be related to physics per se. All right, so Okay, so we can start now see the Before we even you know start discussing upon the plan and other things Let me tell you the the first thing that you will see the the most like can say the basic or The most important difference with respect to the class 10th physics and the class 11 physics is That now physics will be as big or as detailed a subject as The mathematics is in class 11th. Okay in class 10th. You might have seen that physics was You know physics came along with chemistry and biology inside a thin book and You had a mathematics which was equivalent to physics chemistry and biology put together. Okay now in class 11th onwards I don't know how many of you are aware of so that's why I'm telling you all of this Going forward you will have in class 11. You have two books of physics Okay, and that is equivalent to mathematics. You will have two books of chemistry and That is more than mathematics. Okay, and similarly biology also is Biology also has grown fine. So first and foremost, you should understand this that The things have changed a bit. Okay, and you should be geared up for it. All right So, you know, I'm not scaring anybody here. I'm just letting you know that what is the Difference basic difference with respect to 11th and 10th, okay in 10th probably when you have exams of let's say science. All right, so you have one chapter of physics one chapter of chemistry one chapter of biology and Probably you will revise it and number of times before the exam comes All right now since syllabus is huge so big that You may not get time to Revise it again and again before the exam comes. All right, so Make sure that whatever you're doing. You should do it perfect the first time itself Okay, so today, let's say we discussed something. All right, then today only whatever doubts you have Do not hold on to yourself immediately you ask doubts and Solve the assignment and just finish it off Okay, maybe today or before the next physics class. You should be Done with it. All right. So I think I have not introduced myself. I directly started talking about You know the physics itself. So I'll just briefly introduce myself and then I will continue. Okay, I'm sure No one have Has anyone seen me in your school campus or did I teach anyone of you when you were in 9th and 10th. Oh Surai is saying yes Okay Yeah, I remember now. I remember now. Correct. Correct. I Met a couple of you. All right. So see I am Associated with Centrum Academy for since a start. Okay, and I take care of physics for grade 11th and 12th. All right And I teach them, you know At various levels. So I'll just quickly go to my brief Slide intro so that I should not miss on any details as such So I have around 12 years of experience of teaching physics Okay, and in these 12 years, I have taught more than 5,000 students. They are cumulative numbers and You know, I have been training Specifically for these exams. Okay, and I'm sure you are also Aiming for you know one or more of these exams only Okay So is there any any exam that you're aiming for and it is not listed here? Please let me know Okay, and then yeah, I have been fortunate enough to work with the student and Generate these kind of ranks. Okay, and you know, these ranks are all from NPS students only We have just let's say 40 to 50 students who pass out from class 12th every every Year so out of 50 kids We have been able to generate great results and I would like to see your name or your rank here Also, maybe in couple of years. Okay, so yes I have done BTEC from BTEC from IIT Bombay in mechanical engineering and You know, I had a small Experience in in a company called Honeywell. I used to work in Honeywell in aeronautical division Which builds the aircraft then I thought that you know, my interest lies more in teaching. So that's how it all Started. Okay. So this is my brief introduction. I hope everybody now know me so now coming back to the physics and with respect to, you know, kind of Basic requirements you should have before you even start your class 11th journey. Okay So I'll just go to this one Okay, so many of you might be aiming for all of these exams, right? So can can you just type in what are the exams you are aiming for and it is perfectly fine That you can say that I am not clear. Okay, that is all fine But if you're very clear that you're aiming for a particular exam Please type it out so that I have a better idea about the overall, you know, this thing from you Okay others In not not sure is perfectly fine for time being. Okay, but then maybe in a couple of months You should be sure about it. Okay, because Everybody else who is sure might have already started their journey towards it. Okay, and Yeah, I think many of you are interested in KVPI as well Okay And Okay, so in anyone preparing for need here need Medicals anyone. Oh, you're listed down all the exams All the exact you have not left anything. Okay See the I just go through one by one These exams. I'm sure Akhil might have discussed it already. I'll keep it very short and I don't you know, I'll Probably will add up to it only see the first and foremost All these exams which are related to let's say engineering So you can see that there are how many exams are related to engineering per se You have J main J advance bit said you can also say engineering you can go to BSC MSE as well So you have three exams Which are related to engineering. All right, you have Karnataka CT Which will take care of both medical and engineering as well, but let me put it as engineering over here only So all these four exams Okay, all these four exams. They are based out of Same curriculum. Okay, so I'll just write it down See, this is very important before we even start because you should not think that since I am preparing for Bitsat, I will not pay attention to J main or I am preparing for J main I will not pay attention to Karnataka CT. Okay, so The exams of J are Bitsat Okay, the Karnataka CT all these exams. They are based out of Same curriculum Same curriculum In fact, there are these talks going on that Karnataka CT might get merged with J main Okay, so probably by the time you write J Karnataka CT will happen via J main route. Okay, so they are based out of same curriculum Then what is the difference? The difference is the number of questions in the exams Okay, the difference is number of questions in the exam and Probably little bit of difficulty level. Okay number of questions and difficulty level is the difference fine so Right now, I would say that all of you Okay, all of you should aim for at least if you are going through engineering route Okay, all of you should aim for at least J main if not J advanced Because you know, you should not take the judgment of that you are not good Based out of your class 10th performance or your class 9th performance Okay, that is the worst thing you can do I'll just give you my example, you know, I You know, I was studying in a place called Jabalpur. I'm not sure how many of you have heard of it Jabalpur is a small town in In Madhya Padish. Okay, so I have done my Class one to class 11th. Yeah, MP class one to class 11th mid of class 11th I have done in Jabalpur. Okay, and there In class 10th board naturally, you know, your parents you yourself or your friends will Will tell you that it is class 10th board It is very very important take it extremely seriously revise the syllabus hundred times and then go and write the exam Okay, so I was also pretty serious stressed up. So, you know on the day of exam and all I I Used to be very worked up and Given the exam. All right, and during our times. I think now also it is changed but before Maybe one or two years back. There was a great system. So now I got the result and my marks were 71 or 73% out of 100% marks. I got 73% marks. Okay, and I was very happy The reason was I was ranked three in my class and The topper was around 82 or 83% marks. So in that small town There was hardly any competition and I was like rank three in 73% marks. I was extremely happy So then my dad got transferred in Mumbai Bombay. Okay, so there You know, I got shock of my life there. My my dad, you know Make me go to that school that school is candy with the alias cool inside it Bombay itself Okay, so there is a KV IIT which is inside IIT Bombay. So I got admission there and I Was so surprised. I was astonished to Here and see that none of the students in that batch when I was getting when I got admitted in class 11 No one was less than 90% in science batch and I got 73% marks and I got admitted with them. Okay, so naturally that you know Little bit of inferiority complex came in. So I thought that I am not very good Okay, so naturally it made me conscious and also made me work Harder made me a little bit, you know put extra effort so that I could at least compete with them If not, you know, do better than that. Okay, and slowly and slowly as time progressed, you know couple of months later on I Was you know, I had I seen that the topper in the class I think she got around 96 or 97% in 10th. She was struggling in 11th Okay, and I did not find it very difficult Okay, and I have seen several students who have done well in class 10th. They were struggling And several of the students who were unheard of like there was one of my Classmate Angurudra was his name. I remember most of the students who were Angurudra was his name. I remember most of the names. So He he was not heard of till class 10th And suddenly he is excelling in each and every exam. He was scoring so well and later on in class 12th I got 95% overall in in the board exams and I got Got to the J also and I got a seat in IIT Bombay and this guy who was Angurudra, his name is Angurudra. He was ranked 125 and many of the students who did well In class 10th did not do well in any of the comedy exams and Viceroso also there were students who were unheard of suddenly they have done so well Okay, but having said that I'm not saying that all the students who did well in 10th could not do well in 11th and 12th Now what I'm telling you is very important. What I'm telling you is that Here is your chance nice Those who think that they could not get sufficient time. There was a lack of Attention or whatever, you know distraction, whatever excuse you have Okay, and if you think that you could not Do well because of all those excuses Here is your chance in class 11th onwards. Okay, wherein we will be discussing physics chemistry match right from the scratch Your chapter number one in physics is what is physics? Okay, so literally we're going through the scratch. All right, and you know why students struggle in class 11th and They do not struggle much in 10th is Because you have to become little bit analytical in approach Okay, so, you know, I'll be telling this again and again But then you have to get this thing in your head that you should love problem solving. Okay, you should not Be a student who tried to memorize everything Never try to study class 11th and 12 like that Okay, so that is the first Most important thing fine So that is about the engineering that I was discussing about and then of course you have school to take care of Okay, school requirement gets Automatically filled Automatically it will be done if you do Any of the company level preparation any of it if you do your school preparation is automatically done All right, so Don't take a lot of pressure with respect to the school requirement of 11th and 12th Okay, and then of course for the medical students you have neat All right neat neat is something which was offline for For years now probably it will also become online and then of course physics of the need probably the That the questions are little bit more different. Okay? They're a little bit more theoretically oriented than Numerically oriented. Okay, but having said that everything is asked From the same curriculum. Okay, I'm talking about respect to physics and of course biology is one big this thing fine, so Now the question comes what should I refer with respect to physics, right? So yes if if I keep J advance separate For J main bits at Karnataka CT Center module and our LMS is more than sufficient. Okay, and we will be giving you the assignments which Probably right now will not give you the a lot of assignments because we have just started But as a time progress after every class, we will be giving you assignments and it mean it will be hand-picked From various sources apart from that There will be There will be LMS wherein recorded lectures will be there. There will be assignments Online assignments will also be there. Okay, so all these resources are there. Why I'm telling you is that Don't be in a rush of buying books. Okay, that is something which doesn't You know help anyone. Okay, so do not try to accumulate books after books as the year progresses and by the time exam comes Your rate of purchasing book goes up and you pile up huge set of books, which is useless. Okay, so Make sure that you follow what is being told to you. You don't need to let's say purchase any book as such separately and Yeah, but then of course if you are able to do the assignments in time, then you can come back to us and We'll let you know that okay fine since you are able to do the assignments and everything else Which we are telling you you can probably refer to some extra material, which is this again, we will give you and For those who are preparing for J advanced, I have to tell a few things. Okay first of all is that you need to those who are preparing for J advance you need to work at least you know 100% more than everybody else. Okay, that is the fact of the matter. Nobody has cracked J advance without working hard Okay, of course you have to be smart also. Okay, so I Think Akhil might have discussed about the J advance batch. Has he discussed about it? Was J advance batch discussed? Okay, okay, great. So we'll be forming a J advance batch. Okay, and Akhil might have already covered that for you. Okay All right, so let me go to the Anyone has any question you can type in. Okay, let's keep it very interactive You can comment also you can ask a question as well if you have something to write or something to say you can do that Anyone has any comment or anything any doubt till now? No See, this is again something which you should learn. Please ask a lot of doubts and be free about it Okay, and you know, nobody is judging you. Nobody is here to Make fun of your doubts. Okay. In fact, the the silliest of doubts are Probably the most important doubts. Okay I'll tell you one of my friends I'll keep on telling you my experiences because I was also at your age and I was also very very shy to ask all of doubts Okay, but one of my friends he was not shy asking a lot of doubts He was used to ask so silly doubts that sometime used to ask I remember his couple of doubts as well He was like he can the mass of electron be negative You know some something like that he was never feeling shy about it and then after let's say After he wrote J. He got he got civil engineering But then he was inside IIT Bombay and later on he did his MBA from I am and right now He is in London. Okay, so I'm just telling you that how it progresses Okay, so make sure you ask a lot of doubts and anyway when you ask doubts only I can see your doubts Okay, you are sending direct messages to me. It is not like Moxtra, which probably you have seen earlier Okay here when you type the message only I can see the message. Okay Is the J advance batch selective? It is based on interest or skill very good question It is based on of course. It is based on your interest you have to be interested first and second is It is selective we will select and we will recommend we will tell you that since Your performance has been improving and You are able to do the assignments in time. You are not missing any lecture looks like you can Work a little bit more harder. Okay, so we'll make you work harder and in the J advance batch There will be extra assignments extra tests. All right, so yeah, the life in J advance batch is Very difficult, but let me tell you once you clear The J advance you will be most satisfied person when it comes to the you know outcome of your hard work Fine. So anybody else any doubt? Oh Okay Fine, so I'll just brief you about the somebody asked If a person writes only J main what will be the benefit what kind of institution they will get into See when you write J main Most of the institutes other than IIT will take your marks Okay, the NIT is and all the premier institutes other than IIT We'll look at your J main marks and that is That is pretty good. We have couple of students who have cracked J advanced They have got decent rank in J main But they choose not to go to IIT because they were not getting computer science So rather they joined an NIT surat color computer science Okay, so it is not that IIT is the You know the this thing The end game Yeah mass see You're talking about antimatter and all that okay, so no no no we are not discussing that here I'm talking about The silliest of the doubts you can ask Okay, so please ask the silliest of the doubts Okay, and yes one one important thing which I wanted to Tell you which probably many of you have this myth And probably will dissuade you to work very hard is Many you know many kids they think that IIT is all about study Like you work hard get into IIT you again work hard inside IIT And then you keep on working harder harder harder rest of your life So that that is how the you know this thing is but let me tell you that getting into IIT Requires a lot of hard work. Yes agreed But once you are in IIT The life is a lot more fun. Okay, the biggest cultural festival Happened biggest cultural festival in asia You know where it happens Inside IIT bombay The name is moot indigo. You can just search in youtube wherever you want to you will see the detailing of it Okay, biggest cultural fest happens in IIT Bombay biggest technical fest happens inside IIT Bombay There are and and the biggest sports meet biggest college sports meet in india is inter IIT sports That again happens in IIT And there are inter hostel games. There are you know, there are cultural festival every week And there are so many things to explore Other than studies of course. So study will come probably At lesser priority than everything else. Okay, so make sure that You know, you are pretty well aware of it that you what you are aiming at you're aiming for The best time of your life. Okay, so make sure you work hard to get through it Okay, and if you get into some good college, I'm not telling that IIT is the only thing if you get into the Good college you will of course be doing well in your life. Okay, but then if you If you are Not paying a lot of attention Probably then you may have to struggle next four years five years. Okay, so these Times one or two years. This is very very crucial. Okay So so I think no one has any other doubt, right? I can proceed Right. So I think akhil might have discussed about the bridge program. All right, so I'll just Talk about the bridge program of the physics only not the overall thing So this is the Thing which I have planned for the bridge program of physics Okay, first of all during the bridge program. I'm keeping it very light Okay, because I understand that it is happening While you are in class 10th. Okay, of course the exam is in may or june, but back of your mind You have still to write your board exam, which you think that it is very very important Okay, so we'll have just two hour of classes per week for physics Okay, and I think for maths and chemistry also the same and The bridge program is a program which will enable you to accelerate When we study the class 11th, which will enable you to understand Uh The class 11 curriculum lot more better You know than anybody else who has not the basic understanding of these bridge program topics Okay, so We have topics like Vectors And I'm sure many of you have heard of these topics. So vectors You have the basic idea about the vectors those who are whoever with the Centerman class 10 probably uh might be aware of it But how many of you know what is a vector or have you heard of it? Right. I have a poll actually so can you tell me Have you heard of vectors already? All of you take this poll Have you heard of vectors already? Okay, great good to see that good so Everyone has heard of it. Okay So Now, uh, you know, you might have heard about it And you might have the basic knowledge also about it. Okay, but then we will be Getting into details of how you can use vectors or how it is useful in physics Okay, that is what we are going to discuss and it will take around seven hours seven hours is around three classes. Let's say Okay, three classes or maybe I'll try to wind up in two or two and a half classes Okay, and then comes the constrained motion Okay, this is I am not sure whether you have heard of it. Okay, so constrained motion is A topic which is related to geometry of the movement Okay, so there'll be uh some constraints related to if one object moves By let's say one centimeter. How much or with what velocity the second object will move. Okay, so I'll just give you a small Uh, this thing. Let's say if I have this scenario Sorry I have I have just drawn the basic, uh, this thing. Okay, so this is let's say mass m1 This is mass m2 if mass m1 moves by a distance of x1. How much this mass m2 moves That has nothing to do with physics That has to do with the mathematics that has to do with constraint movement Okay, so we'll be learning about that. There'll be many other kind of constraint There'll be wedge constraint pulley constraint and in general The constraints are there which you should be aware of it because many a times Constraint motion is the topic which will stop you To get the answer because everything else is so mechanized everything else is so straightforward step by step You do this and that but constraint motion is like solving a puzzle So you will really enjoy the constraint motion topic whenever we do it. Okay, and then Towards the end we'll be talking about application of calculus in physics Okay, so uh Akhil will be discussing about the brief introduction of the calculus Okay, so he'll be discussing about the limits and derivatives All those basic introduction will be there once he is done We will be talking about how can we how can we use it in physics? Okay, and this is very important this topic because Uh calculus was not used till 10th Okay, and in physics right from the chapter number one class 11th onwards You will have calculus usage of calculus Okay, and unfortunately Students were not taught before class 11 starts. Okay, so we understand that you need to have These basic understanding of the topics before you even take up the class 11th Okay, so more or less all of this will be covered in One one and a half months and then we'll be good to start the class 11th topics. Okay So anyone has any comment or any, uh question to ask You can do so I'll wait for a minute here. Just go through it. Let me know Great. All right. So, you know one other, uh example of my, uh, colleague, which I wanted to take I could not I did not remember so I just give you that example Okay, somebody asked in doubt. So I just hold it for a minute. See, uh, this example is, um A one of my colleague, uh, and one of my classmate actually so, uh Not classmate. Sorry. She was working along with me in in the company in which I was working. So So we used to discuss how your preparation was and all that so I came to know some Astonishing facts which I'm telling you she was all in the rank 15. Okay, one five And Usually we feel that, uh, you know, we buy this material that material We accumulate a lot of material and then we'll be start doing well, you know, what What is her source of knowledge and what all coaching and everything else she has done? First of all, she has not attended any classes any coaching which is actually very rare But then I'm telling you how she has prepared And then she was focusing only on the nce it for physics and mats Okay, and physics more so ever But then have you seen the physics book Class 11 books of physics. Have you seen any one of you nce it textbook anyone have seen it? I think no Nobody has seen it or purchased it. Okay. So anyways, what I'll do I'll circulate the soft copy as well of the class 11th nce it book So there is a set of additional exercises apart from the regular exercise. You have additional exercise in your Class 11 textbook, which people ignore So she used to solve that as well And then she joined some test series from some coaching classes And that is how she prepared and got all in the rank 15 So why why I took that example I took that example to tell you Again that it is not about how many books you have Okay, it's about how many Problems you solve your own without looking at solution How many doubts you discuss with your friends with your peers with your With your teachers. Okay. So I deviated a bit. So that but that was important Okay, how frequently would we have to attend the assignments is the question? See Assignment is something which is given to you after every class So we may not give you right now probably May not we will be just starting so may not have sufficient Number of topics to give you assignment on but as the thing progress after every class We will be giving you assignments We will be circulating the books also sent them books will be there with you Sometimes we'll be giving assignment from those books itself Or we will be giving you assignments as a PDF Okay, which will be given on the whatsapp group All right So once assignment is given Submission date is marked on the class pro So I think all of you are aware of class. It's a class management tool So you will be given a login of that Okay, and you will be against your name when you log in You will have an option to upload the Upload your solutions Okay, so for example, you got the assignment. I get the assignment and then I'm solving it Before my next physics class I will take a picture of it I'll create a PDF You can upload multiple pictures also not a problem And then upload it On the class pro and submit it That is what you have to do after you know Before every physics class physics assignment should be submitted before every maths class Maths assignment should be submitted and it will happen every week Okay, so I think in nine ten ten probably The assignments were not given that frequently if I'm not wrong, but then 11th and 12th There will be regular assignments every week and you know, this is something which is The minimum you can do The least you can do is attend the class do the assignment attend the class do the assignment This is where Your Preparedness starts. This is where you are in the game Okay, after that if you want to get ahead Then you have to do something else if you have to struggle a little bit more Ask more doubts you have to do something different Okay, but then doing assignments is the first and the most important thing Before that You are not even in the game. Okay. Just attending the classes is merely 10 to 20 percent of your Preparedness, okay. There is one more question Is the entire 11 physics or is this only be covered in the bridge program? This is only the bridge program These topics is only for the bridge program Okay, so like I told you the syllabus of physics Has grown leaps and bounds. I would suggest you go through the class 11th Textbook, I'll send you the soft copy of that. Okay. There are I think I think 20 chapters of physics. There are 20 chapters of physics And they are They are not as small as you had in class 10th. Okay. So again, I'm not scaring anyone I'm telling you that this is what it is and the only way to Learn physics is to enjoy it and do not Get into the remembering kind of mode when you look at a problem solve it like a puzzle Okay, physics is going to be Mathematical going forward just like your mathematics was right. You don't need to remember a lot of things You have a problem. You solve that problem by applying some basic concept. You solve it like a puzzle Okay, now physics is also going to be something similar to that Where numericals are there? You create equations And mathematically solve it That is how the class 11th is I hope I have answered that All right So all set to start the class 11th physics now Not exactly the curriculum, but the bridge program. Okay Fine guys. So let us start The class 11th curriculum and then you know, uh, frankly speaking, I am not, uh, you know, first of all, I am not aware who is So to say topper of the class who is who has not done so well in 10th Okay, first of all, I'm not aware and second. I don't care Okay, this is a new beginning Okay class 11th onwards those who have done well till now You have to maintain that and those who have not done well You have a chance We are starting from what is physics all right, since Beginning we are talking about all three subjects physics chemistry and maths. Okay So since I'm talking about the beginning from this, uh, scratch So can anyone tell me what is physics? We'll start from that. Okay. So what is your idea about physics? Let's keep it interactive. Okay, you can you can tell anything. Okay, you can say physics physics is Mass any random thing whatever comes in your mind Please do not hesitate in typing it out. Nobody is seeing that only I am able to see your chat. Okay So what is physics? What is your idea about the physics? Can you just type it? I wanted to see that okay Okay, we have Very good. I can see a lot of you have answered very good And do not keep it very formal Okay, do not keep it like, you know, like some bookish definition. I am not interested Okay, you have to tell what you feel like Okay, you have to tell uh something which Lament terms. Okay. What what what comes in your mind when you hear physics? You you can say that Physics is practical maths. Okay. That is something interesting Of course, it is a branch of science Okay, what else? Study of how everything in nature works and everything works by abiding. Oh my god. This is such heavy words Physics is a study of natural phenomena. Okay Subject that deals with matter space time and motion matter space time And motion. What about charges? You miss that What about heat? What about energy? Physics needs imagination to understand very good It explains mysteries of the world very good. How things move. Okay. That is again a subset of it. So anybody else I like physics. Oh my god. That's the best thing Anything else? See, uh, that's good to uh hear Like, you know, I I really appreciate you telling things Beyond textbook. Okay. You telling things based on what you freely think Okay Good. So keep it up. See, uh First of all, you need to understand the origin of physics how physics has been uh You know created as such You might not be aware that you know when first systematic study of the uh of the nature started as in couple of uh, you know When you know the the first human was there on the earth and couple of more. Let's say we're there and Thunderstorm happened for the first time in their life And it was raining. It was dark lightning and all that so imagine How that guy might have felt Okay, as if god is uh, you know running behind that person Because that guy was not aware of what is happening Okay, so curiosity kicks in because ultimately Nobody killed him Right. It was just a thunderstorm and it happened again and again In his life. So he passed on that information to his kids that listen thunderstorm will happen You will feel as if god is running behind you, but it is all fine And if it is all fine, then it has to be something else other than god running behind you So that curiosity kicks in And then people will uh, see the See in the sky and see that there are stars. Some stars are shining More than some other stars There are and then they realize that there are planets. There are some You know, you know star might be arranged in a particular pattern And then they discovered something called telescope thinking that The universe is that only So if they understand everything which they can see They have understood the entire nature So they devised telescope. They started understanding the universe Okay, and to their, uh, surprise The more and more Stronger telescope they build The universe seems to them bigger and bigger And that mystery never used to end So then they got to know that there is a solar system Of which they are part of And the size of the earth is is like a grain of sand with respect to the solar system And solar system is like a grain of sand with respect to the Galaxy which we in which we are in And galaxy is like a grain of sand with respect to all the galaxies on the universe And then people are talking about multiverse So Then they go crazy That it is extremely difficult to understand the universe. Okay, so The start of the physics is astronomy only When people were trying to understand how the The big objects they behave All right, and then they thought that okay fine It looks very difficult to understand the big objects and their behavior because it is never ending All right, so they thought that why not? Understand the smallest object Because ultimately everything else is built on from that small object So they started breaking it That I will see The smallest particle how it behaves everything else will be the collective behavior of all the things Okay So when they break the substance they reached molecular level atomic level Then they reach the inside the atom. There are proton neutron electron and then later on You know nowadays people are talking about breaking them as well and then Something crazy hits them which is quantum physics And quantum physics tells you that if you observe some phenomena If you observe that phenomena phenomena will change. You're not allowed to observe and that is crazy According to quantum physics, you can be at two places at the same time You are attending class here as well as you are in marathily roaming around and without mask That is all happening. But then if you go and observe if you try to observe That event will be gone. Okay, so It was crazy at that level at the bigger level And it is crazy at the smallest level as well okay, so We are stuck with understanding things In a very limited manner We cannot understand everything about the universe. We cannot understand everything about the tiniest of the particle But we can understand quite a bit about Some common day-to-day life activities and the masses around us. So Physics first of all is not a very structured science Okay for big huge objects like star suns You have theory of relativity And the other things to deal with same theory. You cannot apply to a very very small particle like electron So there are different set of rules for electrons different set of rules for big objects Different set of rules for an object which is moving extremely fast okay, so It is extremely diverse and unstructured. So to say physics But The best part is in class 11 We will be focusing on a portion of the physics Which appears to be very structured and your life is at peace here at least That you know, you'll feel as if everything is structured. So we'll stuck with newtonian physics Okay, which is very very structured Yeah, many different theories sometimes contradict themselves. Yeah, of course, there are wave nature theory wave particle Duality is a contradictory theory, but still they exist. But then you need to understand that When a certain object behave like wave when a certain object behave like a particle, you know, it is like, you know You know just to give you a very interesting this thing example Suppose look at yourself Look at yourself. Don't you think that depending on your mood You behave differently at times compared to let's say you when you're angry you behave differently when you're happy You'd behave differently When you're talking to your parents you behave differently when you're talking to your friends Your behavior is completely different, right? So why not particles? Right. So that is why different theories are there the way they are behaving Changes depending on the scenario itself. So first you need to understand the scenario Okay, then apply the theory, okay But then again coming back to class 11 physics. I'll not deviate too much now, uh first of all physics like some of you have rightly said is You know, we are trying to understand how nature works Okay, how uh Let's put it very bluntly. We are trying to understand how god Runs the universe As simple as that Okay, we are trying to understand that that is physics Okay, but then somebody will say that uh, then, uh You know, it's like a philosophy Philosophy is like, you know, some somebody is giving you Gyan that you have god wants everybody to be happy God wants to wants you to do the good deeds god wants everybody to be friends So that that is also, you know, what god wants you to do, but is that physics? Somebody tells you that uh, you know, my my head is feeling heavy Okay, so You you will probably if you're a philosopher, you'll be like, oh probably you have not slept Or probably you are very sad something like that you will say But then a physics will say that is nonsense your mass of the head remains same okay, so There is A big big difference between philosophy and physics In fact, uh, you know physics although have originated from philosophy only because physics has taken Ph y from the philosophy and i see s from the mathematics. So it has become physics Okay, so when you When you take the philosophy of how The show is running in the universe And try to quantify it Okay, you need to understand that when you try to quantify something So Coming back to the same example when somebody comes and tells you that I am feeling heavy in my head So as a physicist who is very very novice They should ask Exactly how much heavy you are feeling how many grams? Right So if you if you can't quantify it Then it is not physics understand so We are dealing with quantifying the Quantifying everything we observe everything In nature water we observe. We are trying to put some number Okay, talking about mass Talking about mass we have number to associate with it. So let's say 5 kg 10 kg 100 kgs. Okay talking about Heat we have temperature. Let's say talking about speed measures in meters per second talking about Luminos intensity Candela, okay There will be Various other such things which are there in physics Which will try to quantify each and everything you observe if you can't quantify it. It is not physics clear So now first thing we will do here is We are going to talk about What are the You know these these quantities which I am discussing with you which are used To quantify whatever you are observed. They are called physical variables Okay So I want to hear from you. What are the physical variables you are aware of? Okay, so I'll just put a heading here So these physical variables are used to Quantify things. Okay Can you type in what are the physical variables you are aware of and these things are very obvious? I'll write down few things my own for example mass Is something Which I observe and we can measure also mass time Length What else? Okay, great. So we have quite a few now density No, feel free Anything you measure Is a physical variable period anything? So people are telling charge Correct You have energy Very good temperature You have current What else velocity? Okay volume Some of you might say that sir volume and area. They are mathematical quantities. Okay, mathematics is evolved When physics found it difficult to observe things Okay, mathematics helps you To analyze the scenario without observing it directly How do you think? You know relativity theory of relativity have evolved Mathematics is like You can say eyes to the blind man. Okay, they will create an equation Help you analyze things. So mathematics is there to help physics. That's all. Okay. Anyways volume area correct Then mass land time density density. I have not written. I'll write it Density see I want the list to be as exhaustive as possible. So if you If you think that something is missing immediately, tell me density then speed And you can be wrong. Okay, don't worry about being right or wrong acceleration Okay, luminous intensity frequency very good resistance resistance and amount As in number of substances Volume is written Amplitude is length. Don't you think so? Amplitude is a length which I have written here gravity is a force which I have written Force I have written No, I'll write force Then am I missing anything? volume is there Okay There are so many other things so many other things Which you probably have never heard of maybe but Some of you should have Is that it? good, surya torque What else think about something which is not listed here, but you measure it momentum Tension is a force. Don't you think so? Tension is a force Which which is listed here temperature I have written. This is temperature Something which you measure a very very simple thing, which is not listed here, but you measure it. What is that? Distance is length. Don't you think so? Okay, but I'll write it distance somebody is saying that Distance, okay magnetic field good magnetic field Then correct electric field weight is again a force One thing which you have been Measuring since your standard two or three which you're not remembering sound is a wave so You don't measure sound to you. You can say the intensity of the sound Okay, but sound as such Not as I'll write intensity electric potential power All kinds of power probability Probability you can say covered in the amount of substance and all that Registivity Okay, very good Very good Registivity is one What else? Many things are there which you have Seen but you are not able to recollect Gravity is a force which I have anyway mentioned. Okay all right, so What about angle? Angle is also a physics variable Okay angle Have you heard of angular velocity? Have you heard of it? So angular velocity Have you heard of angular momentum angular momentum? Then Have you heard of angular acceleration? If you've not heard of it, it is perfectly fine. It does not matter. Okay, we will discuss it later on when the time comes tangential acceleration Acceleration is a normal acceleration. Okay, which we have discussed Which we have written here. Okay. Why? But they are just adding up different translational velocities. No, no, no See rate of change of Angle is angular velocity Understand that it is a different thing altogether Rate at which angle changes is angular velocity. We'll be discussing it. Just that I'm telling you up front rate of Coverage of the displacement is your velocity. So angular velocity and velocity. They are two different things. Okay Fine. So is that it? Anything else you want to write here You know, the list could go on and on spin Spin is also there. Then, you know, there are so many quantum physics variables The list Goes on So physics is about knowing all these variables Okay, if you have theoretical knowledge about physics And you're not able to quantify or measure anything. All that knowledge is Not useful Okay now When you look at these physical variables Which you have to measure One thing which Will be very very important is this That of course you'll be using numbers to Measure right somebody asked you what is mass You have to tell some real number you have to tell five Or five kg or five point five or seven point six kgs, right? So you have to use a real number to tell these quantities fine apart from these type of quantities there are A set of quantities in which only telling What about the dark matter quantification in that? No, no, no, we are not getting into all that. Okay Dark matter anti matter black hole Time travel time dilation You know, we can discuss it one on one Okay, but not While We are Discussing in a class. Okay. Anyways, so coming back to the class 11 curriculum What I was telling was that The quantities in front of you one set of quantities You can understand by just having a number associated with it Okay, but then there will be some other kind of quantities in which Just telling a number is not sufficient If if I just tell you a number That number will not give you complete information Suppose you ask you ask me What is the force? What amount of force? And if I tell you force is 10 newtons 10 10 newton is a force That information is not sufficient for me To tell whether this pen will move or not If I put this pen like this And if I put 10 newton force vertically down Will this pen move? No Pen will stay there only If I push it like this pen will start moving But in that direction If I push it like that pen will start moving this direction Okay So The point is There'll be one set of physical variables Which will require only number to tell So that you understand complete information If you ask me what is mass If I tell you 10 kgs You are not going to ask me back in which direction the 10 kg Okay, that is useless pointless to ask but Lot of quantities they require You not only to tell the number magnitude But also to tell in which direction they are Okay, so these are called vector quantities Okay, so vector quantity It is not a mathematics concept It is a physics concept Okay, they require you to tell which direction it is Okay, one simple example could be that if I tell you that listen there is A treasure one kilometer from where you are sitting Okay, go and find it That information is practically useless I have to tell you which direction it is right so Anyways, so I want you to tell me The quantities which are written in front of you Can you name those quantities in which you not only need Real number to tell you have to also tell the direction Can you tell me in front of you? What are they? Just name it Okay velocity Where is velocity? Okay, acceleration Is one Then then then then velocity Angular velocity Okay, then momentum Then angular momentum, okay Okay force Okay, somebody's saying time. I'll come back to it Torque as well Okay Why torque other torque some of you might not be completely aware Torque requires a direction sense, okay Okay, current do you need direction? Do you need send? Do you need to know the direction of the current? And the answer is yes Okay, but it is not a vector quantity And why it is not a vector quantity? We are going to discuss later on Although it requires a sense of direction, but it does not follow Rules Vector rules Okay, so we'll discuss in detail later on Magnetic and electric field Magnetic field Electric field What else is angle? Does angle require a sense of direction? If I tell you 30 degrees angle, will you ask which direction? The answer is yes You will ask I'll give you an example here You have these two pens, okay This is the baseline The angle with this pen is 30 degree Won't you ask angle like this is 30 or like that is 30 Like this or like that It is clockwise 30 degrees or anticlockwise 30 degrees Does it make sense? Okay, so even angle my dear friends You may not be knowing it, but angle requires a sense of direction As I tell me, what about area? Does area require a sense of direction? All of you Area requires a sense of direction or not And the answer is Yes, it requires a sense of direction Okay So let me tell you Okay, so let me tell you One example Suppose I tell you that What example I will take Let's say this is the example If I tell you that area of this is 6 meter square 6 meter square is the area Okay So the natural question you should ask back Is the area of the front surface is 6 or the back surface is 6 Don't you think so front and back Back area could be different Area could be different The back could be little bit more protruded like that Okay So area could be different on the backside Fine So area also requires a sense of direction And yes, area is a vector quantity You're going to learn more about that When we discuss magnetic field and electric field Okay So I know it was never discussed till class 10 Okay Because it was not required Okay What else? What about angular acceleration? Is that a vector quantity? Does it require a sense of direction? Yes, it requires Every acceleration requires a sense of direction Okay Now That's it Okay So you can see here Why I'm highlighting all these things Is to let you know That my dear friends You are in physics You are dealing with two kind of quantities Physics is about quantification Letting know how much is the quantity Or what is the number and all that And you have two types of quantities And it is not that vector quantities are lesser in number Or scalar quantities are more in number In fact To Yeah, displacement is also a vector Did I not mention it here? Displacement is not written Displacement is not written But then yes, displacement is a vector quantity A vector quantity is a quantity Which requires both a number to tell what is it And the direction as well Okay So in physics You will see that The quantities which require a sense of direction They are more in number Okay here itself you can count I have randomly written whatever quantities come in mind Probably you can see here that the box quantities They are more in number Okay So that is the reason why We need to understand how every kind of quantity behave Right We have understood since our childhood Like my daughter is in grade one right now She has already started learning how scalars work What is a scalar? It's just a number Okay So she is learning about how you multiply it How you add it How you subtract it How you divide it Okay All those things you are learning right from your childhood Okay So I don't need to tell you that how scalars will behave How to add them How to multiply them How to subtract them or divide it I don't need to tell you that But when it comes to vector Till now You know most of the students will never Discuss or will never get a chance To understand in detail about the vectors But physics is more about vectors So that's the reason why we are getting into details of the vectors Okay We just know okay fine vector requires direction As well as the magnitude But do we know how vectors are added? Do you know how vectors are multiplied? Can I divide vectors with another vector? Okay All these things we should be aware of Otherwise how will I you know deal with forces? Suppose multiple forces are adding Multiple forces are acting on a simple object You have to add them to tell that total amount of forces this Now you cannot add them like numbers Okay, just a simple example If one force from this direction is one Newton Other force from that direction is also one Newton The total force on this pen is zero Right Because one Newton from here one Newton from there it is zero But if you treat it like a number one plus one should be two Okay, so but they are in different directions So that is why you subtracted it So we are going to learn now about the vectors and how they behave Okay We did some adding and subtracting vectors When learning about the force Yeah, of course you did it But then let me tell you I'm going to learn a lot of other things Okay, so let us proceed See like I told you I'm not assuming that anybody knows anything Before coming to the class itself Otherwise what will happen is that some of the students might not be aware of your things They will feel left behind Some of the students might be aware of something So just bear with me I'm sure in just one or two classes You will be seeing something completely new Okay, but then I want to start from scratch Okay, do you do you want me to increase the speed of the class or is the speed fine Do you want me to decrease the speed? Can tell that Is the pace of the class fine Okay, pace is fine But yeah increase the speed Some of you are trying to We can go a little faster Okay, okay All right, so we don't worry, don't worry Physics is changed completely Now you are in class 11th And let me tell you it is going to be a lot more fun And you know the Physics will be fun When you spend time in understanding the basics Okay, the complicated thing Doesn't require your time to understand If you focus on your basic complicated theory And complicated numericals You'll automatically be able to solve it Okay, anyways, so let me start with vectors With some of you might be aware of So vectors is You know, it's a quantity All right, just like scalars It is a quantity which follow different set of rules Okay, it's not like numbers So just like when we were kid We were trying to understand how numbers are added How numbers are multiplied, subtracted and all that We are going to do the exact same way Understanding how vectors behave But then we'll be doing it quickly Okay So vectors First of all can be dealt with Geometrically as well as algebraically Draw this There's a geometrical interpretation of it And there is algebraic interpretation of it Okay, you will understand by using algebra Right now my focus is geometrical Okay, so there are different ways Geometrically how you represent a vector And algebraically how you represent a vector There are two different ways Okay, has anyone of you have seen something like this A1icap plus A2jcap plus A3kcap Has anyone of you have seen like that Okay, some of you have seen it Good, so that is the algebraic notation of it Okay, right now our focus is geometrical Now let us understand how geometrically we can You know, represent a vector First of all, we need to Show the magnitude as well as direction Because vector quantity has a direction And what is the best way you can represent a direction What comes in your mind when you have to tell the direction You'll point out that that is a direction Right, you'll point out like that Okay, and if you have to draw the direction what you do You have to draw the direction what you do Draw an arrow Don't you think so? That's the most obvious thing You draw an arrow like that Okay, now if somebody comes and tells me that no I am more comfortable drawing the direction like that Like this And this tip is the direction Is there anything wrong with this? Is this wrong? Is this wrong? Everyone, there is nothing wrong Okay, there is nothing wrong with it But it is uncomfortable All right, you will see that this is This is very comfortable way you can represent So why to complicate unnecessarily That's a simple and straightforward thing Now the length of the arrow The length tells you what is the magnitude Okay, and the head The arrow head tells you the direction Okay, now if I take this arrow It will be difficult to understand once there are more quantities Yes, that's all If you have let's say multiple arrows are there And multiple cones if you draw like that It will be very difficult Okay, so this is clear Now if I take an arrow Take this arrow And move it in a place Let's say I take exactly this only And I draw it here Here Okay, I have drawn it here Taken this as it is replaced there Has length changed? No Has the direction changed? Direction changed for this arrow or not? Is the direction or the length changed? No Direction is still pointing that way And the length is also the same So we can Geometrically we can move A vector Parallel to itself Parallel to itself Without affecting anything That is first thing Okay And if I reverse this If I reverse the vector like that Direction is reversed Direction is completely reversed But the length is exactly the same Suppose I tell that this vector is A Just like you know if I tell A is a number Okay, I can say this is a vector But then you know you should not get confused whether it is a number or a vector So I put a bar on top of it So a variable with a bar represents a vector Understand? Alright, now if you move it here It remains A only Because neither the direction nor the magnitude is changed But if I reverse it Direction is completely reversed 180 degree Then what happens is Okay, then what happens is I will use I will use sign Sign To tell the direction Okay, negative sign means That it is opposite of what it was earlier In terms of direction The length remains same So if this is A This will be minus A So these are something which are very You can say In basic things But it is important for you to know That if this is A If you invert it, it becomes minus A And you can move it around like that Alright, so this is the Representation, geometrical representation Okay Now let's see how to add two vectors Okay Write down addition With Ajat, can you tell me Can I add Vector with a scalar Does it make sense Can I add vector with a scalar I cannot I cannot add vector with a scalar So when I say addition with Vectors, it automatically means Vector addition with another vector only Alright, in fact I will tell you something Which some of you might be Aware anyways You look at these quantities All these quantities You cannot add One quantity here With any other quantity You cannot add mass with time You cannot add length with density Cannot add Density with speed Luminous intensity with frequency Everything has its own universe Mass will be added And subtracted from the mass only Density from the density only Speed from the speed only Okay, so Not only You cannot add a scalar With the vector You cannot add a physical quantity With another physical quantity Okay, alright So coming back to the addition with the vectors Let's see how it gets Added up and it should be a logical sequence It should be logical Okay, I have a doubt What if We move the arrow upward 90 degree Will the sign be negative See it will become A different vector You cannot represent it With only A Understood If you reverse it You can represent it by using letter A only But if you are rotating it By 90 degree like that You cannot represent it by using A It becomes a different vector Understood Okay, so let's see What is logical Way of adding two vectors Let's say I have a vector like this Okay This is one vector And I have let's say another vector Like that Geometrically I should add up Now What is the Logical way of Adding these two When I add these two vector A third vector will come in Where it is, how to draw that This is vector A and let's say This is vector B Can you draw it? All of you try drawing it Okay, connecting tip Of A with the tip of B Okay, fine, that is Alright, so you can Many of you are telling this Many of you are telling That this is A plus B Which is Correct Nothing wrong My question to you What is the logic Why this should be A plus B The answer is correct But why You can take an example Of Example of a vector quantity and explain it Okay, see If let's say If let's say a mass Goes from This point number one To point number two The displacement is A Okay Then it goes from two to three Okay So when it goes from Let's say one To two One displacement Then two to three Another displacement So it started from here It reached there So when I Add the two displacement It should give me net displacement And net displacement should be One to three Make sense All of you Two balls move at different directions Collide more Different from initial direction okay Pushing a trolley publicly Yes, in a way that is also fine But I have taken the most simple This thing Okay So I hope this is clear Now tell me When you add the two numbers Let's say if I have to add Three and two, three plus two is equal to five Okay, but here The length When you add one to three The length of one to three Is not equal to Length one to two Plus length Two to three They are not equal So when you add two vectors It might result In A lesser quantity Compared to If it was a scalar quantity So that you need to understand Okay And The Magnitude of a vector Magnitude Of A Is represented like this This is represented as Length Length of side Okay, so triangle inequality You are all aware of So if I add two vectors It becomes a third side Which is of course Less than the sum of the two Sites This is triangle inequality Okay So Although it is fine We have to exactly find out What is the length of it Okay, this is called Triangle law of addition Triangle Law of addition We will soon find out What is the exact length of this But before we do that Let me again go back To the point of current I told you that Current even though it has Direction It does not follow vector law of addition That is why It is not a vector Okay So if one current come like this Another current comes like this Okay, let's say two ampere comes here And two ampere comes there Ideally if it is a vector It should become zero It doesn't become zero Four ampere will come from that side Like that Okay, so it is It has a direction but it is not a vector Fine Quickly find out the Magnitude or the length of the third side Okay Sorry about it, let me Let's take some examples And then we will rush towards Finding out the quantity So what I want you to do first Is to add these two vectors Draw it on your notebook A and B And can you show where is A plus B Okay, show me where is A plus B Let me know once you are done basically So what you should do first What you should do first What is the first thing you should do If you have to apply triangle law of addition To add these two vectors What is the first thing you should do All of you Look at how we have added Look at how we have added two vectors Look at it The two vectors which we are adding Two vectors which we are adding Should connect Head to tail This is the tail of B and this is the head of A Head of A should touch the tail of B Okay So Looks like some of you have already Okay Already Done something like that So what I will do I will move B When I move B Like that Which I can do Because a vector Will not Change its magnitude or direction When I move it parallel to itself So it remains B only Okay, it remains B only And A plus B Then will be That This is A plus B Okay And Let me write down first There is A plus B If you join If you join These two points What you will get It has become Palelogram And this vector If you show this as an arrow This is also A A vector parallel to itself Same length Is the same vector So this is Palelogram Law of vectors Palelogram Law of addition Which is nothing but a modification of the Triangle of addition only Okay, let's take another question Then we will proceed Let's say This is This is A Okay And Same kind of scenario This is B Find out what is A Minus B Geometrically how to find out A minus B Can you do that? Okay done You have learned how to add two vectors And now I am asking you How to subtract two vectors What you can do here Is You can change it to A plus Minus B So basically Is same as adding Minus B to A Okay, so if this is B Minus B is what? What is minus B? Minus B is This The opposite direction is minus B That way Okay, and The best thing that They are connected head to tail Alright And then This is your A minus B This is your A Minus B Okay Understood? Can you tell me where is B minus A? Where is B minus A? B minus A is 0 No No Where is B minus A? If this is A minus B Don't you think that B minus A Is equal to negative of A minus B Don't you think so? So Negative of this Vector which is A minus B Is B minus A B minus A is this Opposite of it That's it, clear? Okay, so Okay, so just I will Quickly summarize Few things here Is Is that If you draw A parallelogram like this It's a parallelogram, let's say This is Vector A, this is vector B Then This is also B So This is A plus B, this is what we have discussed Okay, this is A plus B A plus B Where is B plus A? Where is B plus A? If this is A plus B, where is B plus A? Correct, so B plus A Is same as A plus B Okay A plus B Now here Where is A minus B? For A minus B, I will take Reverse of B It becomes minus B And then This is A minus B So one diagonal Is Sum of two vectors Other one Other one represents The difference of two vectors Difference of Two So drawing parallelogram actually helps sometimes Because you not only get the sum of the two vectors You get a difference of two vectors On the same parallelogram Okay So The next thing I wanted to discuss Is The angle between the two vectors How to find out that Angle between two vectors First of all To tell the angle You need two lines, right? I cannot just give you one line Like this, if I tell you that Tell me the angle this line has You don't have any answer Because you need at least two lines What angle it makes So that's what here you need two vectors So how to determine The angle between two vectors Because the main problem You are going to face Suppose two lines are like that Okay So angle between the two line Is this one or that one It is one Or two, which one That is the problem which You will face in vectors So let me draw A diagram here And I am going to ask you Logically what do you think it should be Let's say This is vector A And this is vector B Fine, and let's say I extend the line of A A little bit like that So the angle is Theta Or the angle is Phi What is the angle Theta or Phi And there should be some logic Don't guess it Even if you guess it Please tell why do you think it is Okay, some of you are saying Theta, some of you are saying Phi Why Give the reason also please And reason can be random I don't care that Very sophisticated reason should be there You can say I have seen something like that And I feel it is like that It's fine Cause we are following Okay Others don't sit Quiet Where two vectors meet What if I have the same scenario Like that I am displacing I am displacing a vector Like this becomes A Is this any different Is this any different Don't you think it is same only Where in this is Theta And this is Phi Don't you think it is same I have displaced A parallel to itself Reason, what is the reason Answer may be correct or wrong Very good That's a good reason That's A niche Good Others When somebody tells you Angle What comes in your mind The first thing that should strike in your head Is sense of rotation Sense of rotation Okay So suppose B has to align In the direction of A Listen carefully If B has to align See I am not talking about Rules here I am talking about Why that rule is there Why common vertex should be there Why it has to be like that That is what I am discussing here Can you tell me How much B should be rotated So that Direction of B Should become same as direction of A Is it Theta or Phi It's Theta That's obvious Why it has to be rotated So that it comes in the direction of B That is also Theta That is why Theta is the angle Understood all of you That is why Theta is the angle between the two vectors And Then comes the rule The rule is When you have to find the Angle between the two vectors What you do Connect two vectors Tail to tail You connect and then measure the angle Don't connect like this This is not correct So when you add it You have to connect head to tail When you have to find out the angle You have to connect tail to tail So I think the basic Introduction of vector All of you are aware What is A What is the angle between the two vectors How you add it Technically these are the ABCD of the vectors I think we have Limited time I'll just Start something And will continue it to the next class That's good to know So now What I had started Here Some of the two vectors we are trying to find out Let's say this is One Vector A You have another vector This is vector B This is the angle between the two vectors Let's say angle is theta Okay So geometrically it is very easy What I'll do is that I will draw another line like this And then I will create a Parallogram like that And we will be able to Find out these some of the two Vectors geometrically But then let me tell you It is extremely difficult To accurately find out What is the sum of the two vectors Geometrically Then you have to be very Accurate in terms of drawing Your angles Drawing the length of the vectors Sometime vector could be 10 kilometers Will you draw 10 kilometer line Right So geometrically it is good to know But ultimately You have to use algebra only Okay So I will just draw here A plus B And then we will try to find out the Algebraic formula of The length of A plus B Okay So I will just Give you a little bit of hint And expect you to Lead it forward Has anyone already done something like this Have you found out the length Of A plus B already Earlier Some of you did Good So now if I Do this construction Can you tell me This construction helps you I have done this construction here You can see that What is the biggest help From this construction Everyone The biggest help is I have got I have got Two right angle triangle See throughout the physics I am going To discuss about What you should think What you should write Why it is coming How it is coming Why there is a construction like this How does that help you You get two right angle triangles So you can use Pythagoras theorem twice Which you already know Okay So how you find out something Which you do not know Something you do not know you find it By using what you know What you know Pythagoras theorem You can use it I can use Pythagoras theorem twice Okay So let us try to Since time is running out I just want you to Basically Let us say Just write down the equation That is it Although it is not given You can use this angle in terms of that You can Just write down Pythagoras theorem For two right angle triangle One Two, three, four You have triangle One, two, three And triangle Two, four, three Two right angle triangles are there Can you write down the Pythagoras theorem For both the Right angle triangle And then we are done for the class Let me know once you have written down Sorry, sorry I have written it down I thought it was Okay, done Okay Nowtej, is that your name Am I pronouncing your name correct Nowtej Nowtej is done Others Three to four length Is This Okay One to four length This Can you tell me Four to two length is what What is four to two length This length is how much We all agree it will be B cos theta This is habitanus Okay You guys know the basic Technometry right cos theta is Base divided by habitanus You guys are aware of this right Because Sometimes Students are not I am asking You are aware of this So base is habitanus times cos theta That is what it is written This is what What is this B sin theta Right sin theta is Papandico divided by habitanus Alright so Papandico is habitanus times sin theta So four to two is B cos theta And three to two Is B sin theta Now life is chill Okay You can see here That In a triangle One, two, three You can say A plus B Whole square This is habitanus The length of the habitanus you have to take That tells you the length You can't just say A plus B like that A plus B is a vector I am talking about length So that is why these two bars This is equal to One to two length Is Length of one to four Plus length of four to two Which is B Cos theta That Plus B sin theta Whole square Okay, so for triangle Two, three, four Writing Pythagoras theorem won't help because you get B is equal to B For that, so this is it Alright, so what I'll do I'll just leave you with Quick things which You can after the class Just you can message in the group What I want is You derive expression For A plus B What you have to do just simplify this And get the expression for A plus B And tell me Maximum Value of A plus B And minimum of A plus B Okay, how much it is You can change Angle theta The angle can change At what angle Maximum happens At what angle minimum happens And what is it So I want you to Message it on the group Just want to see Who will message on the group And that will be That's it, okay So we'll meet next week Alright, continue from here And So probably next week And yeah So next week also vectors Alright, so great Interacting with you guys Look forward to Teach you as well For entire year and I'm sure You will generate great result I have heard a lot about you guys From Tushar And the other teachers I think Ankur as well Took your classes, right So let's see how it goes Bye for now, take care Thank you sir Here's your answer in WhatsApp group