A penny is placed on a rotating turntable. where on the turntable does the penny require the largest centripetal force to remain in place?

m = mass of the penny

r = distance of the penny from the center of the turntable or axis of rotation

w = angular speed of rotation of turntable

F = centripetal force experienced by the penny

centripetal force "F" experienced by the penny of "m" at distance "r" from axis of rotation is given as

F = m r w²

in the above equation, mass of penny "m" and angular speed "w" of the turntable is same at all places. hence the centripetal force directly depends on the radius.

hence greater the distance from center, greater will be the centripetal force to remain in place.

So at the edge of the turntable, the penny experiences largest centripetal force to remain in place.