Question

A solid cylinder with mass M and radius R, rotating with angular speed w0 about an axis through its center, is set on a horizontal surface for which the kinetic friction coefficient is u_k. Calculate the accelerations a_x of the center of mass. The answer is u_k *g. I don't know why though, because I keep getting 2u_k*g

Answer 1

The only reason I can see why it's not 2u_k*g is maybe the book used the wrong moment of inertia. the moment of inertia for a solid cylinder is 0.5MR^2. Using MR^2, which is the moment of inertia for a hollow sphere would give u_k*g as the answer.