Q. Two .40 kg soccer balls collide elastically in a head on collision. The first l starts at rest and the second ball has a speed of 3.50 m/s after the collision, second ball is at rest. What is the final speed of the first ball?
Q. A bullet of mass 0.01kg moving horizontally strikes a block of wood of mass 1.50 kg which is suspended as a pendulum. The bullet lodges in the wood, and together they swing upward a distance of 0.4m. What was the velocity of the bullet now before it struck the wooden block? The length of the string is 2 meters.