( √ ? ) 1, and the resultant force is not necessarily greater than the fraction.

( √ ? 2. If the projections of two forces on the same coordinate system are completely equal, then the two forces are not necessarily equal.

( √ ? 3. The direction of constraint reaction must be opposite to the direction of motion restricted by the constrained subject.

( √ ? When the force is translated, the projection of the force on the coordinate axis remains unchanged.

( × ? ) 5. The couple has a projection on the coordinate axis.

( × ? 6. When the force moves along the line of action, the moment of the force at this point is different.

( × ? 7. The force is parallel to an axis, and the projection of the force on the axis is zero.

( ? × ? ) 8. The resultant force must be very strong.

( ? × ? 9. If the projections of two forces on the same coordinate system are completely equal, then the two forces must be equal.

( √ ? ) 10, the line of action of the force passes through the moment center, and the moment is zero.

( ? × ? ) 1 1. Couples can be balanced by the resultant force.

( √ ? ) 12, the force moves along the action line, and the moment of the force at this point remains unchanged.

( √ ? ) 13, the force is perpendicular to an axis, and the projection of the force on the axis is zero.

( ? × ? ) 14. Constraints are devices that restrict the movement of objects.

( √ ? ) 15, the force acting on the rigid body can move along its action line without changing its motion effect on the rigid body.

( √ ? ) 16, the units of moment and couple moment are the same, and the commonly used units are Newton meters and thousand Newton meters.

( ? × ? ) 17. As long as the two forces are equal in magnitude and opposite in direction, the two forces form a couple.

(√) 18, the principle of force transmissibility only applies to rigid bodies.

(√) 19. The magnitude and steering of the torque are related to the position of the torque center, while the magnitude and steering of the couple torque are not related to the position of the torque center.

( × ? ) 20. The living hinge supports two restrained reaction forces.

( × ? ) 2 1, and the torque has nothing to do with the position from the center.

( × ? ) 22. Couples have both rotating and moving effects on objects.

( × ? ) 23. The forces that interact between two objects are always equal in size and opposite in direction, and act on the same object along the same straight line.

( × ? When the force acting on any object moves along the line of action, its effect will not change.

( × ? ) 25. The result of simplifying the plane general force system is the principal vector and principal moment, which are being calculated and simplified.

The heart has nothing to do with it.

( √ ? ) 26. The result of simplifying the plane general force system is the main vector and the main moment, and the calculation of the main vector has nothing to do with the simplification center.

( √ ? ) 27. The force acting on a rigid body can move along the line of action, and the effect on the rigid body remains unchanged.

( × ? ) 28. The projection of the couple on any axis is zero, so it is not necessary to consider the couple when writing the projection equilibrium equation.

( √ ? 29. Internal force is the additional force generated by external force acting on the component.

( × ? ) 30. When the simply supported beam is subjected to concentrated force P in the middle of the span, the shear force in the middle of the span must be the largest.

( √ ? ) 3 1, the bending moment makes the upper tensile lower compression of the beam section negative.

( √ ? ) 32. When the simply supported beam is subjected to concentrated force P in the middle of the span, the bending moment in the middle of the span must be the largest.

( √ ? ) 33. The bending moment diagram should be drawn on the tensile side of the beam.

( ? × ? ) 34. When the bar is stretched, the axial force deviates from the cross section, and the axial force takes a negative sign.

( ? × ? ) 35. When calculating the internal force by section method, the internal force on the same section will be different in size and symbol due to different objects.

( ? × ? ) 36. The bending moment at the beam support will be zero.

( √ ? 37. The difference between pure bending and shear bending lies in whether there is shear force in the beam.

( × ? ) 38. The second force rod must be a straight rod.

(√ )39. Adding a concentrated couple to the beam has no effect on the shape of the shear force diagram.

( × ? ) 40. At the free end of a cantilever beam or cantilever beam, the bending moment must be zero.

( × ? ) 4 1, the extreme value on the bending moment diagram is the maximum bending moment in the beam.

(√ )42. Concentrated force is useful, shear diagram is abrupt, and bending moment diagram is sharp.

(√ )43. The bending moment of a section of Ren Liang is equal to the algebraic sum of all external forces at the center of mass on both sides of the section.

(√ )44. Truss structure refers to the structure in which both ends of each bar are hinged.

( √ ? ) 45. The static moment of the plane figure is related to the coordinate system.

( × ? 46. The greater the bending moment, the greater the bending stress of the main girder.

( √ ? 47. When the plane is bent, all loads act on the longitudinal symmetrical plane, and the lines of action of each force are perpendicular to the axis.

( √ ? ) 48. When the shear force is not zero, the farther away from the neutral axis, the smaller the absolute value of bending shear stress.

( ? × ? ) 49, the compressive capacity of plastic materials is generally greater than the tensile capacity.

( ? X) 50。 The greater the internal force, the greater the stress.

( √ ? ) 5 1, the compressive capacity of brittle materials is generally greater than the tensile capacity.

( √ ? ) 52. The product of the graphic area a and the coordinates from the center of mass of the graphic to the axis is called the static moment of the axis.

( √ ? ) 53. The static moment on the spindle is always zero.

( √ ? Hooke's law shows that in the range of elastic stress, stress is directly proportional to strain.

( √ ? 55. Stress concentration will seriously reduce the bearing capacity of brittle material members.

( ? × ? ) 56. The normal stress and shear stress on the neutral axis are zero.

( √ ? 57. If the static moment of the section to the shaft is zero, then the shaft must be a centroid shaft.

( ? × ? ) 58. Under the action of negative bending moment, the section above the neutral axis is compressed.

( √ ? 59. Area shrinkage is an index to measure the plasticity of materials.

( √ ? 60. When the cross section is constant, the greater the axial force f on the rod, the greater the normal stress σ.

( √ ? ) 6 1, under the action of external force perpendicular to the axis of the bar, the bar will bend and deform.

( ? × ? ) 62. The bearing capacity of rectangular cross-section beams is the same whether they are placed horizontally or vertically.

(√ )63. The yield limit σS of plastic materials is taken as the ultimate stress σ0.

( × ? ) 64, brittle materials take the yield limit σS as the ultimate stress σ0.

(√ )65. The elastic modulus e is related to the material.

(√ )66. As long as there is a figure on the plane, the moment of inertia of this figure to an axis is greater than zero.

( × ? ) 67. The influence of stress concentration on the strength of components has nothing to do with the materials that make up the components.

( × ? ) 68. In the tension (compression) rod, the section with the largest axial force must be the dangerous section.

(√ )69. Bending stress can be divided into normal stress and shear stress. General normal stress is caused by bending moment and shear stress is caused by shear force.

( ? × ? ) 70. The two ends of the rod are subjected to a pair of equal, opposite and collinear forces, and the rod will inevitably deform when it is stretched (compressed) in the axial direction.

( ? √ ? ) 7 1, and the performance index measured under static load at room temperature is bound as the mechanical performance index of the material.

( ? √ ? 72. When the drawing surface is a cylindrical edge, the calculated area of the drawing surface is calculated according to the orthographic projection area of the cylindrical edge.

( ? × ? ) 73. Due to the large load capacity of hollow bearings and the saving of materials, hollow profiles are mostly used for transmission shafts in engineering practice.

( ? √ )74. There is a negative bending moment on the cross section of the beam, with compressive stress at each point on the upper side of the neutral axis of the cross section and tensile stress at each point on the lower side.