physics
posted by Marco .
At the local swimming hole, a favorite trick is to run horizontally off a cliff that is 7.4 m above the water. One diver runs off the edge of the cliff, tucks into a "ball," and rotates on the way down with an average angular speed of 1.6 rev/s. Ignore air resistance and determine the number of revolutions she makes while on the way down.

Multiply the average angular speed, which is 1.6 rev/s rev/s, by the number of seconds that it takes to fall vertically 7.4 meters.
t = sqrt(2H/g) = 1.23 seconds
About 2 revolutions is the answer.