Using energy considerations and assuming negligible air resistance, find the speed of a rock just before it hits the water if it is thrown from a bridge 20.2 m above water with an initial speed of 13.4 m/s? (Verify that the speed is independent of the direction the rock is thrown.)

Answer 1

1/2 mvi^2 + mgh = 1/2mvf^2
m cancels

Answer 2

852