Question 1: Suppose you walk across a room carrying a bucket of water in your right hand. To keep the water from sloshing out, you walk at constant speed, making sure the bucket is kept at the same height above the ground. Which statement is true? a) You exert a force on the bucket and do work on the bucket as you carry it. b) You exert a force on the bucket but do no work on the bucket. c) You don’t exert a force on the bucket and you do no work on it. Answers: b Question 2: TRUE or FALSE: If an object moves from one point in space to another, then work has been done on the object. a) TRUE b) FALSE Answers: b
Question 3: Suppose you push on a heavy table and the table doesn’t move. The work that you do is a) positive. b) zero. c) negative. Answers: b Question 4: A hockey puck slides across the ice and eventually comes to a stop. Which statement is true? a) The work done by gravity is zero. b) The work done by gravity is equal to the gravitational force times the distance the puck slides. c) The work done by gravity cannot be calculated. Answers: A Question 5: You lift a book bag straight upwards off the floor. Which statement is correct? a) You do the same work whether you lift the book bag quickly or slowly. ) You exert the same power whether you lift the book bag quickly or slowly. c) The work you do is zero, making the power also zero. Answers: A Question 6: Any object that has kinetic energy must be a) moving. b) falling. c) high above the ground. d) at rest. Answers: A Question 7: A book is at rest on a tabletop. One student calculates the potential energy as 15 J. Another student calculates the potential energy as 20 J. Which statement is correct? a) One or both of the students must have calculated the potential energy incorrectly. b) Both answers could be correct. c) Both answers are wrong because they use the wrong units.
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