An elaborate pulley consists of four identical balls at the ends of spokes extending out from a rotating drum (?Fig. Q9.18?). A box is connected to a light, thin rope wound around the rim of the drum. When it is released from rest, the box acquires a speed V after having fallen a distance d. Now the four balls are moved inward closer to the drum, and the box is again released from rest. After it has fallen a distance d, will its speed be equal to V, greater than V, or less than V? Show or explain why.
Solution 18DQ Step 1 of 4: This problem can be solved using the law of conservation of energy; That is Loss in potential energy of box = rotational KE of drum + translational Kinetic energy of box M g h = 1 Mv + I 1 2 2 2 v Using h = d and = r M g d= 1 Mv + I( ) v 2 2 2 r
