Q. A 4-kg ball traveling to the right with a speed of 4 m/s collides with a 5-kg ball traveling to the left with a speed of 2 m/s. What is the total momentum of the two balls after they collide?
Q. A 3.0 kg block is attached to a string that is wrapped around a 2.0 kg, 4.0-cm-diameter hollow cylinder that is free to rotate. The block is released 1.0 m above the ground. Use Newton's second law to find the speed of the block as it hits the ground.