Determination of positive and negative torque in torque diagram of mechanics of materials It is said in the book: according to the right-hand spiral rule, the torque T is expressed as a vector. When the vector direction is consistent with the outer normal direction of the cross section studied, t is positive, otherwise it is negative. I want to ask: first, in the right-hand spiral rule, the four fingers point to the direction of torque rotation, or the direction of axis rotation; second, where does the outer normal direction of the cross section point

Determination of positive and negative torque in torque diagram of mechanics of materials It is said in the book: according to the right-hand spiral rule, the torque T is expressed as a vector. When the vector direction is consistent with the outer normal direction of the cross section studied, t is positive, otherwise it is negative. I want to ask: first, in the right-hand spiral rule, the four fingers point to the direction of torque rotation, or the direction of axis rotation; second, where does the outer normal direction of the cross section point

First: in the right-hand spiral rule, the four fingers point to the direction of torque rotation
Second: the normal outside the section is perpendicular to the section and away from the section

How to analyze the force on the object and solve the basic problem of mechanics?

Stress analysis: stress analysis of objects is the basis of solving mechanical problems, which runs through the whole process of high school physics. Therefore, the correct stress analysis is the ability that every student must have. The teacher of Hefei family education center skillfully grasps the method and correct steps of stress analysis in the sprint stage of College entrance examination, which is the key to improve the score

Mechanical analysis of senior high school
Tie two pieces of wood with a rope. If they slow down and the rope is tight, please help me draw the stress analysis for a, B and the overall analysis
□---□
A B exerts a right pull on B, and ab contacts the ground

The whole body is subject to gravity, supporting force and friction
A is subject to gravity, supporting force, friction
B is subject to gravity, support, friction and tension