The wheels of a car have a radius of 11 inches and are rotating at 600 revolutions per minute, find the speed of car in mileage per hour.

Answer 1

arrgh, English units :(

r = (11/12) ft
2 pi r = 5.76 ft/revolution

600 revolutions/min * 60 min/hr =36,000 rev/hr

36,000 rev/hr * 5.76 ft/rev = 207,360 ft/hr

207,360 ft/hr * 1 mile/5280 ft
= 39.3 miles/hr