1、 问题:Two forces applied to the same point on an object ( ) be combined into a resultant force. The point of action of the resultant force ( ) at this point, and the magnitude and direction of the resultant force are determined by the diagonal of the parallelogram formed by these two forces as sides.
B:can not; is not
C:can; is not
D:can not; is
答案: 【can; is】
2、 问题:Adding or subtracting any equilibrium force system from the known force system ( ) the effect of the force system on the rigid body.
A:dose not change
D:some times change
答案: 【dose not change】
3、 问题:The gravity of the object, wind, gas pressure, etc. are the ( ) force.
4、 问题:The following statements about constraints, which is wrong? ( )
A:The force of constraints on an object is reaction force
B:The direction of the reaction force is the same as the direction of displacement that is opposed by the constraints.
C:The force is the reaction by the contraints.
D:The reaction force hinders the motion of the object.
答案: 【The force is the reaction by the contraints.】
5、 问题:The rigid body is in equilibrium under the action of a certain force system. If this rigid body is replaced with a deformable body, its equilibrium state remains unchanged.
1、 问题:The plane concurrent force system can be simplified as a resultant force, the magnitude and direction of the resultant force is ( ) the addition of each component force, and the line of action of the resultant force ( ) the intersection point.
A:equal to; pass
B:not equal to; dose not pass
C:equal to; dose not pass
D:not equal to; pass
答案: 【equal to; pass】
2、 问题:The force F acting on the point A on the rigid body can be moved parallel to any point B, but a couple must be added at the same time. The moment of this additional couple is ( ) the moment of the original force F to the new point B.
答案: 【equal to】
3、 问题:When the object system is in equilibrium, each object that composes the system ( ).
A:All in equilibrium
B:Some in equilibrium, some not in equilibrium
C:Not necessarily equilibrium
D:None in equilibrium
答案: 【All in equilibrium】
4、 问题:When the number of unknowns in the system is ( ) the number of independent equilibrium equations, then all the unknowns can be calculated from the equilibrium equations. Such problem is called statically determinate problem.
D:less than or equal to
答案: 【equal to】
5、 问题:The geometric shape of the truss after being stressed ( ).
D:some changed, some unchanged
答案: 【is constant】
1、 问题:The moment of the force about an axis is a measure of the effect of the force on the ( ) of a rigid body.