1. A 100-meter length of rope is hanging over the edge of a cliff. The rope weights 3 kg/meter.
   1. How much work is done pulling the rope up over the edge of the cliff?
   2. How much work is done pulling half rope up over the edge of the cliff?
   3. How much rope must be pulled up over the edge of the cliff before half the total amount work done pulling the rope is done?
2. A 16-foot cable is hanging from a hook 25 feet above the ground. How much work is done lifting the low end of the cable and lifting it up to loop it over the hook?
3. A spring has a natural length of 1 meter, and 7 Newtons of force is required to keep the spring compressed to \(\frac{2}{3}\) its natural length. How much work would be required to stretch the spring to \(\frac{3}{2}\) its natural length?