Transcript for:
Introduction to Vectors

welcome to electron line and in this series we're going to talk about the concept of a vector now vector as I described here is a mathematical representation of a physical quantity that has both magnitude and direction so what do we mean by that well let me first give you some examples in physics of the kind of things you going to encounter you're going to encounter forces so we can represent the force with an arrow and in this case and let me explain a little bit more here in this case when we draw an arrow to represent a vector the length of the vector the length of the arrow represents the magnitude of that vector the magnitude quantity for example we talk about a force if I draw a long vector I talk about a large force if I draw a small vector in the same direction I talk about a a small force and so the only difference here is that if it's long it's large if it's if it's short then it's small but in either case the direction is the same now if I draw a vector for example in this direction notice that the length of this vector or the length of this arrow and the length of this arrow is about the same so the magnitude would be the same the direction just simply would be different so definitely we use arrows to represent vectors and the length of the arrow simply represents how large that quantity is the direction of the arrow represents the direction in which that quantity is acting in case of the force it would be acting to the right or when acting in this direction so here have a little drawing of somebody pushing a box and so that person exerting a force on that box the direction of force is from left to right and the length of that arrow represents the amount of that force how big that force is here I drew a charge let's say a positively charged object and I drew lines in all directions that represents the electric field around this charged object and the length of these vectors or the length of these lines or arrows I should say represent the amplitude the magnitude of the electric field and of course you can see all the different directions simply represents that the electric field goes out in all different directions here I have let's say a soccer ball and the soccer ball gets kicked in this direction so it will have momentum in this direction momentum is simply a product of the mass which is a scalar quantity we'll get end up just a moment times the velocity and the velocity is a vector component so we have mass times the vector velocity and the result of that is momentum P stands for momentum and that's also a vector the longer I draw the arrow the greater the momentum meaning the greater the mass or the greater the velocity and of course the direction is clearance up in that direction here I drew an example of a car it's traveling from left to right it has a velocity it's like a speed in a direction combined the length represents how fast a car is moving the direction shows you the direction of that movement so I did mention another word I mentioned the word scalar so let's compare what a vector is versus a scalar so we have a vector vs scalar to accentuate the difference between the two effective quantity is simply something that has both a magnitude in a direction the scale is something that only has magnitude for example if I talk about the mass of something that has no direction it's just how much stuff is in it and so that's a scalar quantity but a velocity can be fast or slow so it has magnitude can also have direction that makes it a vector so vectors the quantity that both must be expressed in terms of how large it is magnitude and in what direction it is either what direction object is traveling or the direction that the force is being exerted and so forth so that's the difference between a vector quantity which has both magnitude and direction and a scalar quantity which only has magnitude alright that's a little introduction to vectors in the next so many videos I'm going to show you what we can do with the vectors are going to be adding subtracting multiplying and so forth and that will give you some idea of how to work with that vectors is a very fundamental quantity very fun little thing in physics and you have to really understand this