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Rolling object and friction

  • Thread starter kasse
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[SOLVED] Rolling object and friction

Homework Statement



I want to find an expression for the coefficient of friction when this object starts to skid when we pull it with a force F

http://www.badongo.com/pic/3639015

The Attempt at a Solution



Ff = (mju)*Mg

I found that I can put this into Newton's 2. law for rotation and solve for alpha = 0. But why can't I put it into newton's 2. law for linear motion and solve for alpha = 0 (a = (alpha)*R)?
 
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Answers and Replies

  • #2
Doc Al
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But why can't I put it into newton's 2. law for linear motion and solve for alpha = 0 (a = (alpha)*R)?
You can certainly apply Newton's 2nd law for translational motion. But "a = (alpha)*R" only applies when it rolls without slipping, which is not the case here.
 

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