Question

A car is moving at a rate of 55 mph and the diameter of its wheels is 2 feet.

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

B) Find the angular speed of the wheels in radians per minutes.

Answer 1

so the radius is 1 ft
and the circumference is 2π

55 mph = 55(5280)/60 ft/min
= 4840 ft/min

so rotations per min = 4840/2π
= 770.31
since 1 rotation is 2π radians
angular speed = 4840/(2π) * 2π = 4840 radians/min