A wheel on a truck with radius 18 inches is turning at 12 re

A wheel on a truck with radius 18 inches is turning at 12 revolutions per second, \'the truck in mph? (assume 1 mile = 5280ft)

Solution

Given radius 18 inches

diameter d = 36*Pi inches = 3*Pi feets

N = 12 revolutions per second

speed = 12*3*Pi = 36*Pi feets per second

= 36*Pi/5280 miles/second

= 36*Pi*3600/5280 miles/hour

= 77.112 mph