1. Work Review Answers

2.  1. Force  2. Friction  3. Effort force  4. Efficiency  5. Joule  6. Watt  7. Resistance force  8. Work

3.  9. Kilowatt  10. Energy  11. Power  12. Machine  13. Screw  14. Fulcrum

4.  15.  W = (156Ncos 33)(4.6m) = 602 J

5.  16.  W = F. d = mgd  W 1900J  So, m = ---- = -------------- = 57 kg  gd (9.8)(3.4)

6.  17.  W = (65kg)(9.8m/s 2 )(441m) = 281000 J  281000J  P = -------------------------- = 46 watts  (1.7 hr x 3600 s/hr)

7.  18.  E. De = R. Dr  (250N)(30m)=R(3m) R = 2500 N

8.  19.  (3200N)(6m)  P = ------------------------ = 246 watts  (1.3 min x 60s/min)

9.  20.  W W 56700 J  P = -------- So, t = --------- = ------------- = 945 s  t P 60 J/s