Part a) A billiard ball strikes a second billiard ball that is at rest at 2.25 m/s. The collision is head-on. If the first billiard ball, after the collision, has a velocity of 1.25 m/s in the opposite direction from its original velocity, what is the final velocity of the billiard ball that was at rest? Assume that the billiard balls have the same mass.
Part b) If the collision from the question above took 0.001s, what was the force the first billiard ball hit the second billiard ball that was initially at rest?