A small block of mass \(M\) is projected with an initial speed \(v_0\) onto a horizontal test track. The track is engineered so that the coefficient of kinetic friction \(\mu_k\) between the block and the track increases linearly with the horizontal distance \(x\) traveled, such that \(\mu_k(x) = cx\), where \(c\) is a positive constant. The block starts at \(x = 0\) and comes to rest after traveling a stopping distance \(x = D\).