What is momentum?
Momentum is equal to the product of mass and velocity (p=mv). It has a direction and a magnitude. The most important thing to remember is that momentum is always conserved during a collision unless acted upon by an outside impulse.
Check out this Collision Applet. It will demonstrate that total momentum in a 1-D collision is always conserved.
We know that momentum is conserved in all 2D collisions. The main difference between 2D collisions and 1D is that in 2D collisions there are two components of momentum. If one ball is moving to the right and hits another ball at an angle, then the rightward momentum is conserved. However, there is an upward/downward component. If you know the angle of separation between the two balls, then you can use trigonometry to solve for the momentum of each ball! Here's a problem with an explanation on how to solve a momentum problem by using vectors!
Here's an example problem: If you have a 2 kg ball (ball 1) traveling at 2 m/s and collides with a stationary 1 kg ball (ball 2), what is the momentum of each?
Key:
Ball 1: 5N
Ball 2: 6.67N
