A car is moving at a rate of 73 miles per hour, and the diameter of its wheels is 2.5 feet. (Round your answers to three decimal places.)

Question

A car is moving at a rate of 73 miles per hour, and the diameter of its wheels is 2.5 feet. (Round your answers to three decimal places.)

(a) Find the number of revolutions per minute the wheels are rotating.

(b) Find the angular speed of the wheels in radians per minute.

Answer 1

a)

Circumference, C = 2πr = 5π

73 m/hr = 73 m/hr •5280 ft/m / 60 min/hr = 6424 ft/min

rpm = 6424 ft/min /(5π ft/rev) = 408.965 rev/min

b)

Angular speed, ω = rpm• (radians per revolution) = 408.965•2π = 2569.6 rad/min