1. Figure 12.1  A single force F acts on a rigid object at the point P.
Fig. 12.1, p.363

2. Figure 12.2  Two forces of equal magnitude are applied at equal distances from the center of mass of a rigid object.
Fig. 12.2, p.364

3. Figure 12. 3 Three forces act on an object
Figure Three forces act on an object. Notice that the lines of action of all three forces pass through a common point.
Fig. 12.3, p.364

4. Figure 12.4  Construction showing that if the net torque is zero about origin O, it is also zero about any other origin, such as O’.
Fig. 12.4, p.365

5. Figure 12.5  An object can be divided into many small particles each having a specific mass and specific coordinates. These particles can be used to locate the center of mass.
Fig. 12.5, p.365

6. Figure 12.6  The center of gravity of an object is located at the center of mass if g is constant over the object.
Fig. 12.6, p.365

7. Figure This one-bottle wine holder is a surprising display of static equilibrium. The center of gravity of the system (bottle plus holder) is directly over the support point. (Charles D. Winters)
Fig. 12.7, p.366

8. Figure 12.8 A balanced system.
Fig. 12.8, p.367

9. Figure 12.9  (a) The biceps muscle pulls upward with a force F that is essentially at a right angle to the forearm.
Fig. 12.9a, p.368

10. Figure 12.9  (b) The mechanical model for the system described in part (a).
Fig. 12.9b, p.368

11. Figure 12. 10 (a) A uniform beam supported by a cable
Figure 12.10  (a) A uniform beam supported by a cable. A person walks outward on the beam.
Fig a, p.369

12. Figure 12. 10 (b) The free-body diagram for the beam
Figure 12.10   (b) The free-body diagram for the beam. (c) The free-body diagram for the beam showing the components of R and T.
Fig bc, p.369

13. Figure 12.10  (b) The free-body diagram for the beam.
Fig b, p.369

14. Figure 12.10   (c) The free-body diagram for the beam showing the components of R and T.
Fig c, p.369

15. Figure (a) A uniform ladder at rest, leaning against a smooth wall. The ground is rough. (b) The free-body diagram for the ladder. (c) A person of mass M begins to climb the ladder when it is at the minimum angle found in part (a) of the example. Will the ladder slip?
Fig ab, p.370

16. Figure 12.11 (a) A uniform ladder at rest, leaning against a smooth wall. The ground is rough.
Fig a, p.370

17. Figure 12.11 (b) The free-body diagram for the ladder.
Fig b, p.370

18. Figure (c) A person of mass M begins to climb the ladder when it is at the minimum angle found in part (a) of the example. Will the ladder slip?
Fig c, p.370

19. Figure 12.12  (a) A wheelchair and person of total weight mg being raised over a curb by a force F.
Fig a, p.371

20. Figure 12. 12 (b) Details of the wheel and curb
Figure 12.12  (b) Details of the wheel and curb. (c) The free-body diagram for the wheel when it is just about to be raised. Three forces act on the wheel at this instant: F, which is exerted by the hand; R, which is exerted by the curb; and the gravitational force mg. (d) The vector sum of the three external forces acting on the wheel is zero.
Fig bcd, p.371

21. Figure 12.12  (b) Details of the wheel and curb.
Fig b, p.371

22. Figure 12.12  (c) The free-body diagram for the wheel when it is just about to be raised. Three forces act on the wheel at this instant: F, which is exerted by the hand; R, which is exerted by the curb; and the gravitational force mg. (d) The vector sum of the three external forces acting on the wheel is zero.
Fig c, p.371

23. Figure 12.12  (d) The vector sum of the three external forces acting on the wheel is zero.
Fig d, p.371

24. Figure 12. 13 (a) Truss structure for a bridge
Figure 12.13  (a) Truss structure for a bridge. (b) The forces acting on the pins at points A, B, C, and E. Force vectors are not to scale.
Fig , p.372

25. Figure 12.13  (a) Truss structure for a bridge.
Fig a, p.372

26. Figure 12.13  (b) The forces acting on the pins at points A, B, C, and E. Force vectors are not to scale.
Fig b, p.372

27. Active Figure A long bar clamped at one end is stretched by an amount ∆L under the action of a force F.
At the Active Figures link at you can adjust the values of the applied force and Young’s modulus to observe the change in length of the bar.
Fig , p.373

28. Figure 12.15  Stress-versus-strain curve for an elastic solid.
Fig , p.374

29. Active Figure 12.16   (a) A shear deformation in which a rectangular block is distorted by two forces of equal magnitude but opposite directions applied to two parallel faces. (b) A book under shear stress.
At the Active Figures link at you can adjust the values of the applied force and the shear modulus to observe the change in shape of the block in part (a).
Fig , p.374

30. Active Figure 12.16   (a) A shear deformation in which a rectangular block is distorted by two forces of equal magnitude but opposite directions applied to two parallel faces.
Fig a, p.374

31. Fig. 12.16b, p.374 Active Figure 12.16 (b) A book under shear stress.
At the Active Figures link at you can adjust the values of the applied force and the shear modulus to observe the change in shape of the block in part (a).
Fig b, p.374

32. Table 12.1, p.374

33. Active Figure 12.17  When a solid is under uniform pressure, it undergoes a change in volume but no change in shape. This cube is compressed on all sides by forces normal to its six faces.
At the Active Figures link at you can adjust the values of the applied force and the bulk modulus to observe the change in volume of the cube.
Fig , p.375

34. Figure 12.18   (a) A concrete slab with no reinforcement tends to crack under a heavy load. (b) The strength of the concrete is increased by using steel reinforcement rods. (c) The concrete is further strengthened by prestressing it with steel rods under tension.
Fig , p.376

35. Fig. P12.1, p.378

36. Fig. P12.2, p.378

37. Fig. P12.3, p.378

38. Fig. P12.4, p.378

39. Fig. P12.5, p.378

40. Fig. P12.6, p.378

41. Fig. P12.8, p.379

42. Fig. P12.9, p.379

43. Fig. P12.10, p.379

44. Fig. P12.12, p.379

45. Fig. P12.15, p.380

46. Fig. P12.19, p.380

47. Fig. P12.20, p.380

48. Fig. P12.22, p.381

49. Fig. P12.23, p.381

50. Fig. P12.24, p.381

51. Fig. P12.25, p.381

52. Fig. P12.38, p.382

53. Fig. P12.39, p.382

54. Fig. P12.42, p.383

55. Fig. P12.43, p.383

56. Fig. P12.44, p.383

57. Fig. P12.45, p.383

58. Fig. P12.46, p.383

59. Fig. P12.47, p.384

60. Fig. P12.49, p.384

61. Fig. P12.50, p.384

62. Fig. P12.51, p.384

63. Fig. P12.52, p.385

64. Fig. P12.53, p.385

65. Fig. P12.55, p.385

66. Fig. P12.56, p.385

67. Fig. P12.57, p.385

68. Fig. P12.59, p.386

69. Fig. P12.60, p.386

70. Fig. P12.62, p.386

71. Fig. P12.63, p.386

72. Fig. P12.68, p.387

73. Fig. P12.69, p.387

74. Fig. P12.71, p.387

75. Fig. P12.73, p.387