Coin on an turntable | Exact description of forces Does more static friction between a coin and a turntable mean that it will slip off more or just the opposite of it? When I picturize the situation in my head I land at the first conclusion but I don't find it logically correct. Please help me in solving this problem of a coin slipping on a rotating turntable regarding static friction between surfaces and centripetal and centrifugal forces.
EDIT: Sorry for asking such a poor question I got the answer myself. I am writing down it below.
 A: Static friction between the coin and the turntable is what keeps the coin from sliding away as the disc begins to turn faster. 
Remember the equation for centripetal acceleration:

... and Newton's second law:

So the equation for centripetal force is:

From this equation you can see that, as the magnitude of the coin's velocity increases (i.e., as the turntable spins faster), the magnitude of the centripetal force increases.
The centripetal force is the amount of force required to keep the object in circular motion around the center of the turntable at a velocity, v. 
The static friction between the coin and the turntable is a force threshold. The magnitude of the coin's velocity becomes high enough as the disc spins faster that eventually the centripetal force (the force required to keep the coin from flying away) becomes greater than the static friction between the two surfaces can resist.
A: Answer
First of all imagine that some disk is rotating and on that disc you kept a coin at that instant due to gravity it will no experience reaction force from disc surface in some oblique direction to perpendicular to surface of disc.We can resolve that force into two forces one is normal reaction and other is friction tangential to disc surface(that come into action when one tries to set object in motion in such cases we call it static friction).As disc is rotating with coin placed on it we just tried to set coin in circular motion but it's natural tendency due to inertia is of flying off the surface so friction just opposes this tendency to provide centripetal force.Now as we place coin more and more away from disc axis more centripetal force will be required (by formula that we all know $\omega^2 r$ ) to keep coin in circular motion so more friction will be exerted until we reach critical static friction .Beyond of which it will be slipped off.
