Question

A car is travelling 44 feet per second (30 miles/hour). What is the angular velocity of its 22 inch diameter wheels, in revolutions per minute?

Answer 1

The wheel rotate `1440/pi` revolutions per minute (about 458 revolutions per minute).

Explanation:

If the wheels have a 22-inch diameter, they have a `22*pi` inch circumference.

If the car is travelling at 44 feet per second, this is `44xx12=528` inches per second

Because each 1 rotation of the wheels moves the car `22pi` inches, the wheels will turn

`528/(22pi) = 24/pi` times per second or `(24xx60)/pi = 1440/pi`
revolutions per minute (which is about 458 revolutions per minute).