Date: 31 Physics Exam: Work, Energy and Power Form A Instructions: Directions: Fill in the answer sheet with the correct answer 1. of mass is An object with a mass of 10.0 kilograms is moving at a speed of 5 meters per second. The kinetic energy a. 50 ] b. 2 J c. 250 J d. 125 J 2. Imagine an object held at some height above the ground. It is released and falls toward the ground. Ignoring air resistance or friction, which of the following must be true? a. Before it falls, all of its energy must be potential energy. b. At the end of its fall, all of its energy must be converted to kinetic energy. c. During its fall, the combination of its kinetic and potential energy must equal the amount of potential energy with which it started. d. All of the above are true? 3 . The energy of a moving object is a. kinetic energy. b. potential energy. c. chemical energy. d. nuclear energy. 4 . A 100-kg rock is on a 20-m cliff. If the rock is pushed off the cliff, how much kinetic energy does the rock have before hitting the ground? a. 200 J b. 10000 J c. 15678 J d. 19600 J If no friction acts on a diver during a dive, then which of the following statements is TRUE? 5. a. The total mechanical energy of the system increases b. Potential energy can be converted into kinetic energy but not vice versa c. (KE + PE) beginning = (KE + PE) end d. all the above A 12-kg sled is moving at a speed of 3.0 m/s. At which of the following speeds will the sled have twice as 6. much kinetic energy? a. 1.5 m/s b. 4.2 m/s c. 6.0 m/s d. 9.0 m/s