A lead ball is dropped into a lake from a diving board 5.08m above the water. It hits the water with a certain velocity and then sinks to the bottom with this same constant velocity. It reaches the bottom 4.72s after it is dropped ( Assume the positive direction is upward). How deep is the lake? What is the average velocity of the ball? Suppose that water is drained from the lake. The ball is now thrown from the diving board so that it again reaches the bottom in 4.72s. What is the initial velocity of the ball?