You drive down the road at 39 m/s (88 mi/h) in a car whose tires have a radius of 34 cm.

Question

You drive down the road at 39 m/s (88 mi/h) in a car whose tires have a radius of 34 cm. 
What is the period of rotation of the tires?

2pi*34cm/39= 5.4776 rev/ sec is this right or has to be sec/rev

Henry · Answer

Circumference = 2pi*r = 6.28 * 0.34m = 2.14m/rev. Period = 2.14m/rev/(39m/s) = NOTE: you cannot use cm AND meters. Use 0.34m instead of 34cm to make your units compatible.