SOLUTION: A car has wheels with a radius if 42.0 cm. If the car is travelling at a speed of 90.0 km/h, what is the frequency of rotation of its wheels?

Question 955268: A car has wheels with a radius if 42.0 cm. If the car is travelling at a speed of 90.0 km/h, what is the frequency of rotation of its wheels?
Answer by Theo(13342) (Show Source): You can put this solution on YOUR website!
if the radius is 42 centimeters, then the circumference is 2 * pi * 42 = 263.8937829 centimeters.

there are 100 centimeters to a meter and 1000 meters to a kilometer.

the number of centimeters in a kilometer is therefore equal to 100 * 1000 = 100,000.
if the car is traveling at 90 kilometers per hour, then the car is traveling at 90 * 100,000 centimeters per hour.

90 * 100,000 centimeters per hours is equal to 9,000,000 centimeters per hour.

since the circumference of the tire is equal to 263.8937829 centimeters, then the tire has rotated 9,000,000 / 263.8937829 revolutions per hour.

9,000,000 / 263.8937829 is equal to 34,104.63066 revolutions per hour.

that's the frequency of rotation of the wheels.

the tires rotate 34,106.63066 times per hour when the car is traveling at 90 kilometers per hour.

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