A 0.44 kg ball is thrown straight down from a bridge with an initial velocity of 12.5 m/s. It travels for 1.5 seconds. Find: (a) The height of the bridge, (b) the potential energy of the ball before it is thrown, and (c) the total energy of the ball 2.50 m above the water below.

A1-lb collar is attached to a spring and slides without friction along a circular rod in a vertical plane. the spring has an undeformed length of 5 in. and a constant k =25 lb/ft. knowing that the collar is released from being held at a determine, the speed of the collar and the normal force between the collar and the rod as the collar passes through b.