6. A spring requires a force of 10 N to be stretched 0.2m from its equilibrium position. How much work is required to compress the spring 0.5 m from its equilibrium position? 7. A tank has the shape of a right circular cylinder, with radius 2 meters and height 9 meters. Set up the integral used to find how much work is done in pumping water out over the top edge in order to empty the tank, if the tank is currently full