Answers to Problem Set 4

Solutions

Answers for the even numbered problems:

7-16. (a) W = 1.5 J; (b) K increases.

7-36. W = 1250 J

7-40. (a) W_g = 0.29 J; (b) W_s = -1.8 J; (c) v = [2 (W_s-W_g)/m]^1/2 = 3.5 m/s; (d) The new x would be 23 cm

NOTE: My original solution neglected the work done by gravity, which changed the answers by about 10%.

7-50. Power at 7.5 mi/h is 90 hp.