A coin placed $29\mathrm{.}0$ cm from the center of a rotating, horizontal turntable slips when its speed is $50\mathrm{.}4$ cm$/$s$.$

$($a$)$ What force causes the centripetal acceleration when the coin is stationary relative to the turntable?

static frictioninertia$$kinetic frictioncentrifugal force

Inertia is somewhat loosely used in the English language as a resistance to motion or change in motion. In physics it is precisely defined as the mass of an object. So inertia is not a force.

$($b$)$ What is the coefficient of static friction between coin and turntable?