\fFigure 2 A dart of mass md is launched straight upward toward a block of mass mb that hangs at rest from a string, as shown in Figure 1. Immediately before the dart collides with the block, the dart has a speed '00. The dart then collides with and sticks to the block, and the dart-block system travels upward to a height H before the system comes to rest, as shown in Figure 2. What is the change in momentum of the dart-block system immediately before the collision to the instant when the system comes to rest? Zero mdv0 @ 0 ,L :5 .1. 3