Problem 1.138

A horizontal plane supports a stationary vertical cylinder of radius \(R\) and a disc \(A\) attached to the cylinder by a horizontal thread \(A B\) of length \(l_{0}\) (Fig. 1.32, top view). An initial velocity \(v_{0}\) is imparted to the disc as shown in the figure. How long will it move along the plane until it strikes against the cylinder? The friction is assumed to be absent.