Physics Lesson: Kinematics Acceleration Equations Part 1 Kinematics for High School

[username6333]

Keep making these videos, they are great.

[mmacritics]

"Therefor, who cares about time." Made me smile a little bit. I bet all of the students learning from these teachers get straight A's. THANK YOU VERY MUCH!

[PhysicsEH]

@mmacritics Thanks for taking the time to let us know you liked our videos.

[AlexandtheUniverse]

Thank you very much for all these videos! I was struggling with my physics homework and this helped me out very quickly! Much appreciated!

[PhysicsEH]

@AlexandtheUniverse Thanks for taking the time to let us know you liked our videos.

[Caaarrl94]

I'm so glad i found you :) i have my physics exam on wednesday and i hardly know anything because my teacher just goes on, and on, and on, and on, about nothing that makes any sense xD

You explain things so clearly :) thanks

[bat974rtiuo]

can d means distance?

[OHUHAHEH]

Can you explain equation number 5. i just don't get that one.

[xcimena]

You have no idea how much I love this guy right nowwww!!!! You explain everything so clearly!! :)

[ZerkosXD]

Why do clever people always use a black board, when we have much better things like whiteboards?

[Bakugantsuvai1]

Can you show me the proof to formula number 4?

[SarahDemiFan]

@PhsicsEH1 we use S= displacement and U= initial velocity

[PhysicsEH]

@SarahDemiFan Hi. Yes sometimes it depends on the textbook you use so you may see some of our videos have different variables.

[SarahDemiFan]

Hi am from grenada Caribbean and in my highschool we only use 4equations y is d reason u use 5 ??? (jus curious)

[PhysicsEH]

@SarahDemiFan If you have all 5 then you can always find one that solves for what you need. If you use 4 then you may have to solve for one variable to use in another equation which means you need to use 2 equations. It may be a little more work but its not more difficult so 4 will work just fine.

[dfsauruguaya]

Thank you for the explanation! Really helps, one question though; why did you look for the equation that doesnt have V2 in it? Thanks for your help.

[PhysicsEH]

@dfsauruguaya There are 5 variables in the equations V1, V2, a, t and d. Each equation has 4 of these so if you are trying to figure out what equation to use you look at what you have (in this case V1, a, and t) and what you need (in this case d). This means one of the 5 variables is not in your "given" list or in your list of what you want (in this case the missing variable is V2) so you must choose an equation that does not have V2 in it or you will not be able to solve for d. hope this helps.

[musiclover279]

Thank you; simply understanding Physics makes it all the more enjoyable.

[silica61]

@PhysicsEH In a situation where I use the Kinematic Equation x=vt +1/2(at^2) to solve for time and I get two positive values, how do I know which one is the right time?

[PhysicsEH]

@silica61 If you get 2 times and they are both positive it measn that it is at that height twice. The first time is the one as the object is moving upwards and the second time is the one when it is falling back down to the ground. You would need to know if the object was thrown up and landed on the roof or if it hit the object on the way up. I think you would be given some information in the question to let you know. Hope this helps.

[PhysicsEH]

@silica61 Thanks for the comment. Glad we could help.

[MsHomework123]

Two go-carts, A and B, race each other around a 1.0 km

track. Go-cart A travels at a constant speed of 20.0 m/s.

Go-cart B accelerates uniformly from rest at a rate of

0.333 m/s^2. Which go-cart wins the race and by how

much time?

[PhysicsEH]

@MsHomework123 A travels with constant speed so t= d/v = 1000/20 = 50s. B accelerates so d=V1t +1/2at^2 so 1000=0 + 1/2 *0.333*t2 so t= 77s. Car A wins. How far did B go in the 50s that car A took to win. d=V1t + 1/2at^2 so d= 0 + 1/2*0.333(50^2) = 416m The car won by 1000-416 = 584m. I hope I got it right.

[MsHomework123]

@PhysicsEH Can you show me how to get 77s...?

[MsHomework123]

@PhysicsEH can you show step by step for finding 77s...because I need to show my work and I am not getting the same answer!

[PhysicsEH]

@MsHomework123 First line d=V1t +1/2at^2 Second line sub in d = 1000, V1 = 0, a= 0.333 so you get 1000=0t + 1/2 *0.333t^2 Third line the zero t becomes zero so 1000 = 0 + 0.1665t^2 Forth line 1000 = 0.1665t^2 Fifth line divide both sides by 0.1665 so you have 1000/0.1665 =( 0.1665/0.1665)t^2 Sixth line 6006 = t^2 seventh line take square root of both sides so Sq-root 6006 = sq-root t^2 Eight line 77.5 = t I hope this helps.

[PhysicsEH]

@MsHomework123 From my last email you have d=V1t +1/2at^2 so 1000=0 + 1/2 *0.333*t2 so multiply the 1/2 *0.333 you get 0.1665 so now you have 1000=0.1665t^2, you need to now get rid of the 0.1665 so divide both sides by 0.1665 and you get 6006=t^2, take the square root of both sides and t = 77s. Now you want to know how much time it won the race by. It took Car A 50s (from my last email to you) and 77s for Car B so Car A won by 77 - 50 = 27s. I think that works. I hope it helps.

[SnuggieDougie]

A field Hockey Player starts from rest and accelerates uniformly to a speed of 4.0 m/s in 2.5 s.

a.) Determine the distance she travelled.

When using your help, I get 12.5m, yet my textbook says the answer is 5.0m. I am really confused now, please help.

[PhysicsEH]

@SnuggieDougie Hi. V1 = 0m/s, V2 = 4m/s, t=2.5s Find d = ? Its hard to write the equation you need to use because it is a fraction and so it does not look right when I type it on one line. The equation is number 1 in the video Use d=[(V1+V2)/2]*t so( V1+V2)/2 = (0 + 4)/2 = 2 then multiply this by t or 2.5 = 2*2.5 = 5m I hope this helps.

[suki1615]

I'm praying this helps for my test tomorrow.

[PhysicsEH]

@suki1615 I hope your test went well. I also hope it helped.

[BboyScar1]

Who would dislike this video, this guy is a genius! Thank you!!

[PhysicsEH]

@BboyScar1 Thanks for the comment, Glad to help.

[matthewhouston69]

Thank gid for this guy i have a test on tuesday and i learned more from this video then my teacher taught me

[PhysicsEH]

@matthewhouston69 Thanks for letting us know they helped. Good luck on your test.

[onaugust4]

OH MY GOODNESS, i have a physics test on acceleration tomorrow and i was hopelessly lost until i saw this. i have learned more from watching this 4 minute video than i have from listening to my physics teacher for the past 3 weeks. thank you so much!

[PhysicsEH]

@onaugust4 Thanks for the very nice comment. We love the hear they helped.

[Soren515]

You are a saint. This really clears up the confusion I had in physics. Thank you so much for your time and knowledge.

[PhysicsEH]

@Soren515 Thanks for taking the time to let us know we helped. Best of luck with your course.

[PhysicsEH]

@Soren515 Thanks for taking the time to let us know we helped. Best of luck with your course.

[achakhasa]

my ap physics teachers just reads the equations from the section then gives us practice problems. that we solve, and he merely gives us the correct answer at the end. no lesson plan, no worked out examples, nothing. we're expected to read the book and figure it out ourselves. so thank you for doing what my shitty teacher is supposed to do. i appreciate it a lot.

[PhysicsEH]

@achakhasa We are very glad that we could help you out. Best of luck with your course.

[dhaccessories]

Wow. Thank you so much for the video. It helped me so, soooooooooooo much. Before watching this, I had no idea how to start solving the problems. I'm so glad I found this video.

[PhysicsEH]

@dhaccessories Thanks for letting us know it helped. Best of luck with your studies.

[SaugaTricks]

I've been trying to figure out something very simple (two things in fact) for some time now and you answered both in one short video! I'm glad I came across this video. Thank you very much

[PhysicsEH]

@SaugaTricks Hi. Thanks for letting us know. We're glad we could help you.

[dhart2]

As simple as that. :)

[PhysicsEH]

@dhart2 Yup. Thanks for letting us know we helped.

[PhysicsEH]

@Sweetchocolaterose V1=0, V2=26, t=6. a) use equation 1. d=((v1+v2)/2)t = ((0+26)/2)6 = (13)6=78m[S]. b) use equation 2 but rearrange it so a=(V2-V1)/t = (26-0)/6 = 4.33m/s^2[S]. c) average V = total distance / time = 78/6=13m/s[S] d) Since the acceleration is constant, the average velocity happens at half the time of the motion or 6/2=3s. I hope this helps.

[djwestbrook36]

whoa check dat beard out!

[Typhani830]

I have to learn my physics in one night for my test. I missed a few days of school and the end of the grading period is tomorrow. This video cleared up a lot! Thanks for taking the time to make it! Great help!!!! :)

[PhysicsEH]

@Typhani830 Hi. Thanks for the great comment. We're glad to help.

[lalkhan001]

I like your explanation. Thanks for sharing

[PhysicsEH]

@lalkhan001 Thanks for the comment. We're glad we could help.

[SuCKeRPunCH187]

@PhysicsEH is it true that you can an infinite number of constant acceleration kinematics equations, not just five?

Also, are there kinematics equations for non constant acceleration?

[PhysicsEH]

@SuCKeRPunCH187 Hi. You can derive more equations from the 5 that will work for specific applications such as projectile motion, but the basic 5 will get you the answer also. There are formulae for non constant acceleration and the calculations can be more complicated so most physics courses jut use the ones for contant acceleration. Thanks for the great question.

[usakid32]

The actually answer is 15 m. At the end, instead of taking half of 10, he took half of 100, which gave him 50 * 3, when it should have been 5 * 3.

[usakid32]

@usakid32 Never mind, I missed the squared. My fault.