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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: 

$4300 \textrm{ rev}$

Giancoli 7th Edition, Chapter 8, Problem 8

(0:45)

Chapter 8, Problem 8 is solved.

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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.