[SOLVED] Spring and Block A spring is compressed 6 cm and an 6 kg block is placed against it. when the spring is released the block shoots forward along a rough, horizontal surface traveling 1.2 m before coming to a stop. The coefficient of kinetic friction between the block and the surface is 0.4. Find the speed acquired by the block as it leaves the spring. I try to use conservation of energy but I'm having trouble since I'm not given k or v (find k would be the second question).