Question:

A bicycle with tires 68 cm in diameter travels 9.2 km. How many revolutions do the wheels make?

Source: Giancoli, Douglas C., Physics: Principles with Applications, 7th Edition, 2014.

Quick Answer:

$4300 \textrm{ rev}$

### Transcript for this Giancoli solution

This is Giancoli Answers with Mr. Dychko. With each revolution of the bicycle wheel, it travels a linear distance equal to the circumference of the wheel and the circumference is*π*times

*d*. So we multiply the total distance that the wheel travels,

*l*, which is 9.2 kilometers and times by 1 revolution for every circumference,

*πd*, and we get our answer. So that's 9.2 times 10 to the 3 meters times 1 revolution for every

*π*times 68 times 10 to the negative 2 meters— this is centimeters converted into meters times 10 to the minus 2— and that gives 4300 revolutions of the bicycle wheel.