A 5kg block is held against a spring of force constant 20N/cm, compressing it 3cm. The block is released and the spring extends, pushing the block along a horizontal surface. The coefficient of friction between the surface and the block is 0.2. a) Find the work done on the block by the spring as it extends from its compression to its equilibrium position. b) Find the energy dissipated by friction while the block moves the 3cm to the equilibrium position of the string. c) What is the speed of the block when the spring is at its equilibrium position? d) If the block is not attached to the spring, now far will it slide along the surface before coming to rest?