Revolutions and radius of wheel

[rcmango]

Homework Statement

A string is wound tightly around a wheel. When the end of the string is pulled through a distance of ? cm, the wheel rotates through ? revolutions. What is the radius of the wheel?

Homework Equations

The Attempt at a Solution

i'm confused about this simple problem because i believed that displacement and revolutions were the same for theta in a kinematics problem like this: theta = 1/2(w0 + w)t

what equation would I use to solve such a problem.

 

[Integral]

All you need is the relationship between circumference and radius. You get the circumference from the length of string pulled and the number of revolutions.