Acoin of mass m rests on a turntable a distance r from the axis of rotation. the turntable rotates with a frequency of f. what is the minimum coefficient of static friction between the turntable and the coin if the coin is not to slip?

Explanation:

= normal force acting on the coin

Normal force in the upward direction balances the weight of the coin, hence

= frequency of rotation

Angular velocity of turntable is hence given as

= distance from the axis of rotation

= minimum coefficient of static friction

static frictional force is given as

The  static frictional force provides the necessary centripetal force , hence

Centripetal force = Static frictional force

answer: the metamorphic rocks are formed when they are exposed to high pressure and high temperatures. this happens when one of the earth's plates comes in contact with the other plate by traveling in opposite directions, straight into each other or slipping under one another. the friction that is caused by this activity results in   melting of rocks and when it cools they are known as metamorphic rocks. this process needs a controlled amount of pressure and temperature otherwise it may turn into magma.