13. A steep waterside accelerates riders at 4.5m/s the entire time they are on the slide. How long is the alide if it takes 4.2seconds to get to the bottom (assuming they started from rest)?

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.