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December 21, 2014

December 21, 2014

Posted by **Mario** on Thursday, October 1, 2009 at 11:32am.

(a) What is the coefficient of static friction?

(b) What is the coefficient of kinetic friction?

- Physics -
**drwls**, Thursday, October 1, 2009 at 12:03pm(a) Let s be the coefficient of statice froction and k be the coefficient of kinetic friction.

From the info on the angle at whic slidign starts,

M g sin 30 = M g s cos 30

tan 30 = s

(b) Solve for the acceleration rate a after sliding begins. It slides a distance X in time T.

a T^2/2 = X

a = 2X/T^2

Then solve for k using Newton's second law.

M a = Mg sin 30 - M g k cos 30

a/g = sin 30 - k cos 30

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