Solve the problem.
-Each tire of an automobile has a radius of 1.25 feet. How many revolutions per minute (rpm)does a tire make when the automobile is traveling at a speed of 115 feet per sec? Round your answer to the
Nearest tenth.
A)14.6 rpm
B)878.5 rpm
C)1372.7 rpm
D)1757.1 rpm

Question

Quizplus · Accepted Answer

The circumference of a tire is given by $C = 2\pi r$, where $r$ is the radius. For a tire with a radius of 1.25 feet, the circumference is $C = 2\pi(1.25) = 2.5\pi$ feet. To find the revolutions per minute, we first convert the speed from feet per second to feet per minute (115 feet/sec * 60 sec/min = 6900 feet/min). Then, we divide this distance by the circumference of the tire to find the number of revolutions per minute: $6900 \div 2.5\pi \approx 878.5$ rpm.

Solve the Problem. -Each Tire of an Automobile Has a Radius of 1.25