a block of mass m rests on a block of mass m1 which is on a tabletop. a light string passes over a frictionless pulley and connects the blocks. the coefficient of kinetic friction between the blocks and between the block of mass m1 and the tabletop is the same. a force f pulls the upper block to the left and the lower block to the right. the blocks are moving at a constant speed.

Suppose a force of 60 n is required to stretch and hold a spring 0.1 m from its equilibrium position. a. assuming the spring obeys hooke's law, find the spring constant k. b. how much work is required to compress the spring 0.5 m from its equilibrium position? c. how much work is required to stretch the spring 0.6 m from its equilibrium position? d. how much additional work is required to stretch the spring 0.1 m if it has already been stretched 0.1 m from its equilibrium? a. kequals 600