physics
posted by Shundale .
A diver springs upward with an initial speed of 2.1 m/s from a 4.5 m board.
(a) Find the velocity with which he strikes the water. (Hint: When the diver reaches the water, his displacement is y = 4.5 m (measured from the board), assuming that the downward direction is chosen as the negative direction.)b. What is the highest point he reaches above the water?

(a) His kinetic energy will increase by M g H, where H = 4.5 m. Therefore
V2^2 = V1^2 + 2 g H
V1 = 2.1 m/s
(b) The increase in height at the highest point, h, is the elevation at which the potential energy increases by (1/2)MV1^2
2 g h = V1^2