posted by sarah .
A quarterback throws a pass that is a perfect spiral. In other words, the football does not wobble, but spins smoothly about an axis passing through each end of the ball. Suppose the ball spins at 5.8 rev/s. In addition, the ball is thrown with a linear speed of 17 m/s at an angle of 53° with respect to the ground. If the ball is caught at the same height at which it left the quarterback's hand, how many revolutions has the ball made while in the air?
The time in the air is 2*Vsin53/g
Multiply that by 5.8 rev/s for the number of revolutions.