Question

If a car has tires with a diameter of 28 inches and is traveling at 55 mph, how fast are its tires spinning, in rpm^ prime s (revolutions per minute)? [There are 63,360 inches in 1 mile) Round your final answer to 2 decimal places .

Answer 1

Answer:

The tires are spinning at 660.49 revolutions per minute.

Step-by-step explanation:

The speed of the tires (v) is the same that the speed of the car, so to find the angular velocity of the tires we need to use the equation:

$\omega = \frac{v}{r}$

Where:

r: is the radius of the tires = d/2 = 28 inches/2 = 14 inches

$\omega = \frac{55 mph}{14 inches*\frac{1 mile}{63360 inches}} = 2.49 \cdot 10^{5} \frac{rad}{h}*\frac{1 h}{60 min}*\frac{1 rev}{2\pi rad} = 660.49 rpm$              

Therefore, the tires are spinning at 660.49 revolutions per minute.

   

I hope it helps you!