 channel for physics. Please subscribe my channel. Hello and welcome back to another episode of physics partner. Today we are going to discuss a newly injected topic in IGCSE physics curriculum for both the code 0625 and 0972 physics and the topic is addition and subtraction of vectors by graphical method. Before understand the addition of vectors we need to recall the concept of both physical quantities. There are two types of measurable physical quantities, scalar quantities and vector quantities. A scalar quantity is a type of a quantity that has just magnitude and no direction. Therefore it is simply a number accompanied by an identical unit. For example length, mass, speed, electrical current etc. There are scalar quantities and they have no direction. A scalar quantity has no specific direction of application. Its value will be precisely the same in every direction. What about the vector quantity? A vector quantity has magnitude with the unit in a particular direction. So specifying the direction of action and its value or magnitude is obligatory while defining or stating a vector quantity. In a vector quantity magnitude represents the size of the quantity you can see here on the screen which is also its value. While direction describes the side let's say west, east, north, south etc. Any change in the vector quantity reflects either magnitude shifts change in direction or change in both of them. Some examples of vector quantities are forces, acceleration, weight, shearing stress, velocity, electrical field intensity, centrifugal force etc. The addition of vector is not as straightforward as addition of scalars. In scalars you just add simply the magnitude of two physical units which are same in nature but in vector condition vector have both magnitude and direction and one cannot simply add two vectors to obtain their sum. To better understand this let's consider an example. An example of a car which is traveling 10 miles north and 10 miles south. Here the total distance travel is 20 miles. If you carefully look the displacement is zero because the car is came back on the same position where it started. So the distance travel is 20 miles whereas the displacement is zero. The north and south displacement are each vector quantities and the opposite directions cause the individual displacements to cancel each other out. In this video let us explore ways to carry out the addition of vectors. So let's see how we can add vectors with each other by graphical method. This method is also called head and tail rule or it's also called a triangle addition method. Okay let's say this vector is vector A. The magnitude of the vector is the length of this vector. If this vector is representing force let's say one centimeter is one Newton. So this is now nine Newton force and now I am adding one more. Let's make it a perpendicular to it. You can see in one hand you can just join the tail and then you can add one more vector which is called resultant vector. The resultant vector will be initiated from tail to tail and head to head. So this will be considered as your resultant vector. If we add two scalar quantities like let's say 9 kilogram and 4 kilogram it will be 13 kilogram. So I am going to add one resultant vector which is my purple one you can see on the screen and you can see it's from tail to tail and head to head I can make and this resultant vector magnitude is 9.9. In scalar quantities 9 plus 4 is 13 but in vector quantities 9 plus 4 is not 13 this is because of the change of direction. Let's try one more. This time I am going to take three vectors. So let me take one is blue one here I am going to make it and another vector which is green one. Let me make it little different types of and I place it here and the third vector is a red one. Let me take into another direction let's say it's here. How can we make a resultant vector? So simply we can produce one tail from the tail and head from the head and join them and it becomes my resultant vector like this. So right now my resultant vector is magnitude is 7.1 and its angle is 81.9 from the initial one. So in vector quantities you notice that angle is also very important along with magnitude. Okay let's quickly review on subtraction of vectors. Remember the subtraction of vectors is same as addition of vectors. The only difference is the flip of the direction the reverse the direction. For example you can see here two vectors A and B B is perpendicular to A when you try to subtract B from A you need to flip the B with the reverse direction. So it becomes A minus B that's all otherwise is same as the addition of vectors. I hope you enjoyed the video. I hope the video is useful for you. Thank you very much and take care of yourselves. See you in the next video. Goodbye.