6. A 12 kg cat is resting on a tree which is 7 m above the ground. Calculate its potential energy. 7. A girl runs up a 5 meter high flight of stairs with a mass of 20.4 kg Calculate her potential energy. 8. A ball of mass 2 kg is kept on the hill of height 3000 m. Calculate the potential energy possessed by it? 9. A 2000 kg car is on the edge of a 100 m cliff. What potential energy does the car possess relative to the base of the cliff? 10. Suppose you drop a 0.5 kg textbook from the third floor of a building to a friend who stands on the ground. If the book is 38 m from the ground, what is its potential energy?​