The two-bar mechanism consists of a lever armAB and smooth link CD, which has a fixed sm...

The two-bar mechanism consists of a lever armAB and smooth link CD, which has a fixed smooth collar at its end C and a roller at the other end D. Determine the force P needed to hold the lever in the position 0. The spring has a stiffness k and unstretched length 2L. The roller contacts either the top or bottom portion of the horizontal guide.