How Fast Does the Rim of a Spinning Disk Travel?

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Nitrag
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Problem 13.30
A thin, 60.0g disk with a diameter of 7.00 cm rotates about an axis through its center with 0.240 J of kinetic energy. What is the speed of a point on the rim?

Homework Equations


m=.06kg
r=.035m
KE=.240J

The Attempt at a Solution



K=(1/2)*I*(w^2)
I=(1/2)*M*R^2

I'm using the formula above but I'm not getting the right answer. My numbers seem way to small. I eventually get w(omega) alone. Where do I go from here. Do i need to solve for the length to figure out rad/s then convert to m/s?

Perhaps I am approaching this wrong.
 
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