A ball mass 2kg rests on a slope of angle 60 degrees. If it is stationary, calculate the coefficient of static friction
Because the ball is stationary, the sum of the forces acting on it must be equal to 0. We can split the ball's weight into two components: perpendicular and parallel to the slope.W(para)=2gsin60W(perp)=2gcos60The frictional force is equal to the coefficient of friction multiplied by the normal reaction force. We know this reaction force, N, must balance W(perp)N=W(perp)=2gcos60Since the frictional force (F=uN) must be equal to W(para), we can find the coefficient of friction by dividing W(para) by N, to give u=tan60
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