A car drives down the road at 80 kilometers per hour The tir

A car drives down the road at 80 kilometers per hour. The tires of the car each measure 65 centimeters in diameter. Assuming no slippage, about how quickly are the wheels of the car spinning in revolutions per second?   

Solution

The car, i.e tires are travelling at 80 kmph

This translates to 80 * 5/18 or 200/9 meters per second

The tires measure 65 cm in diameter

The distance travelled by the tires over one revolution is the circumference
.. which is 0.65pi meters

Now, 200/9 meters travelled in one second

And since 0.65pi is one revolution, 200/9 meters is 200/9 divided by 0.65pi,
i.e 10.8823892712407067

So, approx :

10.88 revolutions per second ----> ANSWER