A 2-lb block rests on the smooth semicylindrical surface k at A. An elastic cord having a

Question:

A 2-lb block rests on the smooth semicylindrical surface k at A. An elastic cord having a stiffness of k = 2 lb/ft is attached to the block at B and to the base of the semicylinder at C. If the block is released from rest at A, determine the longest unstretched length of the cord so the block begins to leave the cylinder at the instant θ = 45°. Neglect the size of the block.