A 10-lb block is attached to an unstretched spring of constant k = 12 lb/in. The coefficients of static and kinetic friction between the block and the plane are .6 and .4 respectively. If a force F is applied to the block until the tension in the spring reaches 20 lb and then suddenly removed, determine (a) how far the block will move to the left before coming to a stop, (b) whether the block will then move back to the right.