point e) Wha PHYSICS Energy Two Conservation of Energy, Work, Potential and Kinetic Energies 1) A force of 200 N is used to lift a mass up to a position 6 m above its original position. a. What was the total work done on the mass? b. What is the potential energy of the mass? c. Where did the potential energy come from? 2) Anne Ville, the ironworker, (30 kg) is at an initial height of 3 m. She is raised by a crane to a new height of 7 m. a. What is the initial potential energy of Anne? b. What is the final potential energy of Anne? c. What is the change in potential energy? d. What is the total work done on Anne? e. If Anne was released from her final position, what will be her speed when she passes her initial position? f. What will Anne's speed when she hits the ground if released from 7 m? 3) Knute Yeer's son Junior (35 kg) is resting in a tall tree, h = 137 m, when he sees a box of chocolate covered mint candy on the ground. Because of his excitement, he leaps straight upward at a speed of 22 m/s. a. What is Junior's total energy when he leaps out of the tree? b. What is Junior's total energy when he reaches his maximum height? What form is the energy at the maximum height (classical turning point)? c. What is Junior's maximum height? d. What is Junior's total energy when he lands gracefully on the ground? What form is the energy when he reaches the ground? What is Junior's speed when he lands on the ground? f. What is Junior's total energy when he is 88 m from the ground? In what form is the energy? g. What is Junior's speed when he is 88 m from the ground? 4) Mrs. H attempts to shoot an apple off the top of Mr. H's head with a bow and arrow while she wears a blindfold. Mrs. H is standing on a tall ladder so that the arrow is 18 m above the apple. The mass of the arrow is 0.012 kg and the arrow is fired with a velocity of 185 m/s. a. What is the arrow's potential energy relative to the apple? b. What is the kinetic energy of the arrow when fired? c. What is the total energy when the arrow is fired? d. What kind of energy does the arrow have when it hits the apple? e. What is the speed of the arrow when it hits the apple? 1) 1200 J 2) 882 J 3) 55, 461 J 4) 2. 12 J 1200 J 2058 J 55, 461 J, PE 205.35 J From the work 1176 J 161.7 m 207.47 J 1176 J 55, 461 J, KE KE 8.85 m/s 56.3 m/s 185.95 m/s 11.7 m/s 55, 461 J, PE + KE 38 m/s