A truck with 46-in.-diameter wheels is traveling at 45 mph.

Question

A truck with 46-in.-diameter wheels is traveling at 45 mph.

Round answers to 2 decimal places as needed.

How many revolutions per minute do the wheels make?  rpm 

What is the angular speed of the wheels in radians/min?  rad/min 

Answer 1

63360 inches in mile

60 min = 1 hour

45 mph = 45/60 miles / min = 0.75 miles / min

0.75 miles / min = 63360 * 0.75 in / min = 47520 in / min

wheel rim = pi * 46 = 144.51 in

rpm = 47520 in / min / (144.51 in) = 328.84 1/min

each round is 2pi rads

anglular velocity = 328.84 1/min * 2*pi = 2066.16 rad/min