Physics Unit 7

Today we started Unit 7 (woohoo!!) which is based on momentum and collisions. We spent the day learning about momentum and and impulses. Momentum, whose variable is p (capital P is for total momentum), is a vector quantity, which means it can be added like vectors. To find momentum, you would do mass times velocity. And in order to find the total momentum, all you have to do is add up the individual momentums. The Law of Conservation of Momentum states that in a closed system, the momentum of a system is always conserved. Impulse is the average force upon an object multiplied by the time the force is acting on the object. Impulse is also the change in momentum of an object, and its variables are I and J (totally makes sense, I know).

In case my explanations were confusing and you would have preferred equations, here they are:
p = momentum
P = final momentum
I or J = impulse

F = force
p = mv
P = p1+p2+p3...
I = F • change in time
I = change in momentum = mv - mvo

In today's lab, we used air tracks and used two gliders to measure their collisions and see how their velocities changed based on their masses and how they hit each other. We used rubberbands at first so that when the gliders hit, they would bounce off each other. This kind of collision is called an elastic collision. We also replaced the rubberbands with two metal pieces, one side with a pin and the other with wax, so when they collided, they would stick together rather than bounce apart. This kind of collision is called an inelastic/sticky collision.

Also, we could all use a little Bill Nye in our lives, so here is a video where demonstrates aspects of physics, if anyone wants to take a walk down memory lane (I was going to just add the whole episode link, but it didn't work).