Angular velocity (S)
A coin of mass m is placed a distance R from the center of a record player turntable. The coefficient of static friction is μs. The angular speed of the turntable is slowly increased to a value of ω0, at which point the coin slides off. Find ω0.Solution
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Solution
Firstly, we ignore the tangential acceleration because we are told it is small.Newton’s second law in the vertical direction gives
Newton’s second law in the horizontal direction gives S2.10
making use of Key Point 5.10.On the point of slipping, the frictional force is given by (S2.8)
FF=μsFNCombining these results we find