A 1-kg steel ball is fixed onto a 2-m cord to make up a pendulum that pivots about O, as shown in the diagram. The pendulum is released from rest in a horizontal position, and when the ball is at its lowest point it elastically strikes a 1-kg block sitting at rest on a shelf. The coefficient of kinetic friction between the block and shelf is 0.10. Assuming the shelf is long enough, how far does the block slide before stopping? 1.0 kg 20 m