Achild in a tree house uses a rope attached to a basket to lift a 24 n dog upward through a distance of 4.8 m into the house. how much work does the child do in lifting the dog?

In a game of pool, ball a is moving with a velocity v0 of magnitude v0 = 15 ft/s when it strikes balls b and c, which are at rest and aligned as shown. knowing that after the collision the three balls move in the directions indicated and assuming frictionless surfaces and perfectly elastic impact (that is, conservation of energy), determine the magnitudes of the velocities va, vb, and vc.