ANSWERS TO PROBLEMS

Some of these answers are only approximations, for often the value of a quantity that is only approximately known must be used in the computations. For example, it may make a difference whether the specific gravity of mercury is taken as 13.6 or as 13.56.

CHAPTER I (PAGES 14-15)

4. 224 lb., 12.70.7 lb. 17. 20 lb. 20. 13 ft. from

1. 2.8 mi. northeast. 3. 184 lb., 34 degrees north of east. 26 degrees from the 200-lb. force. 10. 64.6 lb. 11. 200 lb. 14. 22 lb. 15. 44 lb. 16. 24.3 in. from the 10-lb. weight. 18. 2.7 ft. from load. 19. (a) 424 lb. heavier end.

(b) 424 lb.

mercury. 6. 134 lb.

CHAPTER III (PAGES 35-36)

2. (b) 9.84 × 105 bars; 14.31 lb./in.2 3. (a) 1.96 × 105 bars; 14.7 cm. (b) 0.617 × 105 bars; 4.64 cm. mercury. 5. 0.09 lb./in.2 7. (a) 0.147 × 105 bars; (b) 2.14 × 105 bars; (c) 4.21 × 106 dynes. 9. 1.48 × 1010 dynes. 12. 112.7 gm. 13. 3.33. 14. 12,480 lb. 15. 64 lb. 16. 24.7%. 17. (b) 205.9 lb. 18. (a) 4.1; (b) 0.89. 19. 6.66 lb.

CHAPTER IV (PAGES 51-53)

1. (a) 1.57 × 106 bars; 118.1 cm. mercury; (b) 1.14 × 106 bars; 85.5 cm. mercury. 2. 718,000 dynes/cm.2 3. 2120 lb./ft.2 4. 964,600 bars. 5. 7.9 oz. 7. 78,000 cu. ft. 9. 12.5 lb./in.2 11. 248 cu.m. 12. 10.2 m. 13. (a) 0.154 gm. (b) 0.095gm. (c) + 0.059 gm. 14.5.74 m. 15.8.09 m. 16. 1.03. 18. 170 cm. mercury.

CHAPTER V (PAGES 64-65)

7. (a) 7.5 ft. (a) 204 ft. 16. 5.8 ft.

3. (a) 29.8 mi./hr. (b) 3.0 mi./hr. 6. (b) 40 ft. (b) 30 ft. 8. (b) 125 cm. 10. (b) 924 ft. 12. (b) 100 ft. 13. (b) 116 ft./sec. 14. (a) 189 ft./sec. (b) 5.90 sec. 15. 465 ft. 17. 153 ft.

CHAPTER VI (PAGES 88-89)

1. (b) 64 cm. 2. (b) 10,000 dynes. 3. (b) 12,000 dynes. 6. Acceleration = 16 ft./sec.2 7. 270 lb. 8. 880 sec. 9. (a) 6 ft./sec. (b) 25 ft. 10. 204.8 ft./sec. 11. (b) 108.9 cm./sec.2 12. 131.2 lb. 13. (a) 4.69 slugft./sec. (c) 1 ft./sec. 14. (a) 8000 gm.-cm./sec. (c) 6000 dynes-sec. 15. (b) 9.88 ft./sec. 16. 17. 1.97 × 105 dynes. 18. 3.79 × 106 dynes. 19. 1815 lb.

1. 74,900 ft.-lb.

CHAPTER VII (PAGES 107-108)

2. 294 × 10o ergs. 3. 37.6 4. 8. 424.26 ft.-lb. 9. (a) 90,000 ft-lb. (b) 150 lb. 12. (a) 22.5 ft./sec.

11. 30.98 ft./sec.
13. (a) 100 cm./sec.
(b) 1743 ft.-lb.
22. 1.09 H. P.

14. (b) 5×105 ergs.

(d) 3.09 ft.-lb. 16. 5.71 H. P.
23. 312 lb.

24. 0.27 H. P.

27. 0.038 Η. Ρ.

(b) 10 cm./sec. (c) 128 ft./sec. 20. 80.7 lb.

5. 160,000 ft.-lb.

10. 1.58 × 105 ft.-lb. (b) 25,312.5 ft.-lb. 15. (a) 1.16 slug-ft./sec. 18. 0.606 H. P. 21. 16 H. P. 25. 6250 lb. 26. 12 H. Р.

13. (a) 211.2 ft.-tons. (b) 0.64 H. P. 14. 393 ft.-lb./min.

1. 188.5 cm./sec.

CHAPTER X (PAGES 137-138)

2. (a) 14.21 × 104 dynes.

4. (a) 315.8 cm./sec.2 5. 4.74 × 104 dynes. 6. 125.7 cm./sec.

3. 0.507 sec.

7. 24.82 cm.

10. (a) 1.0002 sec. (b) Lost 17.3 sec.

11. 3.55 × 10o ergs. 12. 1.26 sec.

8. 2.007 sec. 9. 984 cm./sec.2

CHAPTER XI (PAGES 153-154)

1. 0.0391 slug-ft.2 2. 12.34 ft.-lb, 5. 1.12 slug-ft.2 6. 2.83 × 105 dyne-cm. 8. (a) 14.06 slug-ft.2 (b) 17.66 lb.-ft.

3. 1.26 joules.

4. 9870 ft.-lb. 7. (a) 3.51 slug-ft.2 (b) 6.6 lb.-ft. 2. 0.00416 dyne.

CHAPTER XII (PAGES 161-162)

3. 1.003. 7. (a) 0.2131 dyne. (b) 0.0002174 gm.

5. 20.53 ft./sec.2

6. 25.8 lb.

CHAPTER XIII (PAGES 175-176)

1. 9 ft./sec. 2. 39.6 lb./in.2 3. 17.7 ft./sec. 4. 27.3 lb./in.2 5.77 ft./sec. 6. 32 ft./sec. 7. 5568 ft.-lb. 8. 1210 ft. lb. 9. 192 ft.-lb./sec. 10. 3.8 ft.3/min. 12. 39,700 ft.3 13. 28,650 ft.3/hr.

2. 1.54 cm.

CHAPTER XIV (PAGE 193)

3. 0.40 cm. 4. 0.40 cm. 6. (a) 0.72 cm. (b) 0.37 cm.

CHAPTER XV (PAGE 202)

5. 0.0297 cm. 6. 0.0283 in. 8. 0.1 in. 9. (a) 49 × 107 dynes/cm.2 (b) 4×10-4. (c) 12 × 1011 dynes/cm.2 10. 0.0005. 11. (a) 27.3 lb.-ft. (b) 857 ft.-lb./sec.

CHAPTER XVII (PAGES 226-227)

4. 0.030 cm. 6.400.43 cc. 7. 6720 lb./in.2 8. 1124 cc. 10. 497.85 gm. 11. 5.4 сс. 12. 93.0 lb./in.2 13. 39.9° C. 14. 864.8 cc. 15. 63.8 cm.

CHAPTER XVIII (PAGE 234)

5. 37.5° С. 6. 17.5° С. 8.30.9° C. 9. 13.4° С.

CHAPTER XIX (PAGES 248-249)

7. 1.41 × 104 lb.

3. 344.5 cal. 4. 26.4 m. 5. 4.7 H. P. 6. 5.1%. 8. 1.9 H. P. 9. 2.24 B.T.U. 10. 427 gm. 11. 1272.5 B.T. U.

CHAPTER XX (PAGES 264-265)

5. 1250 cal./sec. 6. 20° C. 8. 5.63 × 108 ergs/sec. 10. 1550 kg.-cal.

CHAPTER XXI (PAGES 291-292)

3. 6.61 gm. 7. 7.6° С. 8. 161° С. 9. 17.6° C. 11. 240 gm. 13. 31.2° С. 14. 26.1° С. 15. 15,026 cal. 16. 1.51 kg.

CHAPTER XXII (PAGES 315-316)

1. 10.57 gm./m.3; 62%; 1.05 cm. mercury. 2. 3.4%.

CHAPTER XXIII (PAGE 324)

C

1. 36.4 H. P. 2. 1.2 lb. 3. 11.7%. 4. 1.57 H. P.-hr.

CHAPTER XXIV (PAGE 359)

7. 11.86 gm.

1. 12.4 ft./sec. 2. 5.7 ft./sec. 4. (a) 26.4 cm. (b) 571 cm. 5. 5626 ft. 7. 278 sec. 1. 8. 1.176. 11. 2906 sec.-1.

2. 0.6 C. G. S. unit. 5. (a) 0.064 C. G. S. unit. (b) 0.209 C. G. S. unit. 6. (a) 0.4 C. G. S. unit.

CHAPTER XXVIII (PAGES 433-434)

1. 5.3 amp.

6. 103 volts.

3. 80 volts. 4. (b) 1080 volts.
5. (b) 103,680 joules.
7. (a) 3.2 volts. 10. 500 watts. 11. 0.6¢.

12. 8.8.

13. 3.24. 14. (a) 28 volts. (b) 5kw. (c) 1120 watts.

CHAPTER XXIX (PAGES 442-443)

2. 9331 cal.* 3.

10. (a) 125 watts.

667 sec.* 5. (b) 216,000 cal.* 7.58.4° С. 9. 22 с. (b) 12.5 kw. (Power factor = 1.)

CHAPTER XXX (PAGES 460-463)

1. 4.33 ohms. 2. (a) 2.5 amp. (b) 275 watts. 3. In 5-ohm, Q.36 amp.; in 10-ohm, 0.18 amp. 4. (a) 112.2 volts. (b) 0.22 ohm. (c) 22 watts. 5. (a) Loss in battery, 8 volts; in wires, 3.2 volts; in instrument, 8.8 volts. * Equation (35) was used.

6. (a) 0.3 amp. 7.0.353 amp. 8.0.273 amp. 9. (b) 1.0 volt. 10. 32 volts. 11. (a) 0.5 amp. (b) Dry cell, 1.4 volts; gravity cell, 0 volt. 12. (a) 0.1 amp.

(b) Dry cell, 1.48 volts; gravity cell, 1.2 volts.

13. (a) 135 volts. Shunt, 19.98 amp.;

19. (a) 40 amp.

22. (a) 3.46 ohms.

(c) 110 volts.

25. 0.2 ohm.

1. 41.9 dynes.

8. 0.008008 ohm.

CHAPTER XXXII (PAGES 493-494)

2. 16 dynes. 6. (b) 270 dynes-cm. 7. (b) 120 dynes. 9.267.7 ohms. 10. 9086 ohms.

CHAPTER XXXIII (PAGES 521-522)

2. 0.4 volt. 3. 5 volts. 4. 0.0138 volt. 6. 0.005 volt. 7. 500 cm./sec. 8. 0.00210 volt. 9. 200,000. 10. 0.013 sec. 12. 320 volts. 14. 180 R. P. M.

5. (a) 2513 lines.

CHAPTER XXXIV (PAGE 530)

CHAPTER XXXV (PAGES 548-549)

1. (b) 0.000033 m. f. 2. 710 m. f. (approx.). 3. (a) 112.5 C. G. S. E. S. units. (b) 0.000125 m. f. 6. 0.0119 m. f. 7. (a) 0.286 m. f. 9. 7.2 joules. 11. 133.3 volts.

CHAPTER XXXIX (PAGE 591)

2. 0.0253 henry. 3.7.03 m. f. 4. 300,000 sec. -1