A rock is thrown downward with velocity 10 ft/sec from a bridge 100 ft above the water. how fast is the rock going when it hits the water?

A rock is thrown downward with velocity 10 ft/sec from a bridge 100 ft above the water. The velocity of the rock upon impact on the water can be solve using the formula:

V = sqroot (2gy) where g is the acceleration due to gravity and y the height

V = sqroot (2 (32.2 ft/s2) (100ft) = 80.25 ft/s