Homework 7
Due by 1:00pm Thursday, February 27, 2003
Textbook Problems, Chapter 6
Conceptual Questions (p. 180): 6, 8
Problems (p. 181): 8, 15, 28, 35, 57, 58
Brief Answers
Conceptual Questions
6. A slow moving car could have more kinetic energy than a fast moving motorcycle because of the car's larger mass.
8. The force does 4 times as much work in the second doubling (using the Work-Energy theorem).

Problems
8. (a) 1.80x103 J (b) -1.20x103 J
15. 6.40x105 J
28. (a) -44 J (b) 44 J
35. (a) KE = 0 J, PE = 392 J, E = 392 J
(b) KE = 196 J, PE = 196 J, E = 392 J
(c) KE = 392 J, PE = 0 J, E = 392 J
NOTE: PE and E depend on where h=0 is chosen to be.
57. 1 kWh = (1x103 Wh)(3600 s/h) = 3.6x106 J
58. t = 73.5 s