A bicycle tire with a 12-inch radius is making 175 revolutions per minute. Find the linear speed in miles per hour.
12 in = 1 ft
The inear distance covered in one hour =
2pi ( 1 ft) * 175 revs/ min * 60 min = 65973 ft
Divide this by the number of feet in a mile = 5280 = 12.49 mi /hr