The assignment was to observe the collision between two magnetic air pucks and determine the momentums and velocities at various points. This type of collision was elastic, and i had to prove this. So since this collision should be elastic, the total momentum before should equal the total momentum after the collision. I ended up with the total momentum before the collision to be 0.493 m/s*kg and the total momentum after the collision to be 0.520 m/s*kg. This answer resulted in a 5.2% error. Following these calculations, I had to disscuss why this percent error occurred. Any ideas?