A good baseball pitcher can throw a baseball toward home plate at 87 mi/h with a spin of 1710 rev/min. How many revolutions does the baseball make on its way to home plate? For simplicity, assume that the 60 ft path is a straight line.

First, convert 87 mi/h to ft/min.

87 mi/h * (5280 ft/mi) * (1 h / 60 min) = 7656 ft/min

The time to reach the home plate is:

t = 60 ft / 7656 ft/min

t = 0.00784 min

The number of revolutions made in that time is:

n = 1710 rev/min * 0.00784 min

n = 13.4 rev

Rounding to 2 significant figures, the ball makes 13 revolutions.