A 263-g block is dropped onto a vertical spring with force constant k = 2.52N/cm. The block sticks to the spring, and the spring compress 11.8 cm before coming momentarily to rest. while the spring is being compressed, how much work is done (a) by the force of gravity and (b) by the spring? (c) What was the speed of the block just before it hit the spring? Ignore friction.