Calculate the moment of the force to the axis
Publish: 2021-04-15 03:22:34
1. Take opening the door as an example
you pull the door outward
the door doesn't move
if you push harder, the door will fall off<
this is the meaning of the moment of force to the axis
to the fixed point
you can use the seesaw as an example
three children
two people sitting on the left and right sides
one child sitting in the middle
whether the children in the middle exist or not will not affect the children's game on both sides
in the middle
you pull the door outward
the door doesn't move
if you push harder, the door will fall off<
this is the meaning of the moment of force to the axis
to the fixed point
you can use the seesaw as an example
three children
two people sitting on the left and right sides
one child sitting in the middle
whether the children in the middle exist or not will not affect the children's game on both sides
in the middle
2. First, the moment of the force P to point a is calculated, and the direction is along the Z axis, and then it is projected to ab; The projection of the moment of the force to the point on an axis passing through the point is equal to the moment of the force to the axis.
3. Your understanding of the right hand rule is biased. The moment of the force on the axis is r cross multiplied by F. the application method of the right hand rule is: four fingers first point to the direction of R, and then bend to the direction of F to make a fist (the bending direction of the four fingers must point to the direction of F), and the direction of the thumb along the axis is the direction of the moment
if the palm direction changes (keep the four fingers pointing to the same direction), then after the four fingers are clenched into a fist, the four fingers can not point to the direction of F, but to the opposite direction of F, which is bound to draw a wrong conclusion. So your idea is wrong
question add:
I think I know what your problem is. When studying the moment, the axis, R, and F are perpendicular to each other. The axis is the direction of the moment, and R is the arm of force perpendicular to the axis and F. it is a vector and the direction is from the axis to F. F must be a component perpendicular to the axis. The moment of the component parallel to the axis to the axis is 0, which is not considered in the study of moment
in your example, the direction of R is not from O to the point of action of the force, but from the x-axis to the point of action of F, and is perpendicular to both the x-axis and F. So you can tell that the moment of F on the x-axis must be along the axis. Of course, if the thumb is the same as the X axis, it is positive, otherwise it is negative.
if the palm direction changes (keep the four fingers pointing to the same direction), then after the four fingers are clenched into a fist, the four fingers can not point to the direction of F, but to the opposite direction of F, which is bound to draw a wrong conclusion. So your idea is wrong
question add:
I think I know what your problem is. When studying the moment, the axis, R, and F are perpendicular to each other. The axis is the direction of the moment, and R is the arm of force perpendicular to the axis and F. it is a vector and the direction is from the axis to F. F must be a component perpendicular to the axis. The moment of the component parallel to the axis to the axis is 0, which is not considered in the study of moment
in your example, the direction of R is not from O to the point of action of the force, but from the x-axis to the point of action of F, and is perpendicular to both the x-axis and F. So you can tell that the moment of F on the x-axis must be along the axis. Of course, if the thumb is the same as the X axis, it is positive, otherwise it is negative.
4. When a force is applied to a particle, the force can be regarded as a vector. A force applied to a straight line (plane) can be regarded as a quantity (algebra).
5. Find your own textbook. The formula in the textbook is very detailed. The first problem is that the moment of space force to point is equal to the vector diameter multiplied by the force vector, which is equal to the moment of force to point. In fact, it is a determinant, and the solution is very simple
the second question is actually that sentence, the projection of the moment of the space force on the x-axis is equal to the moment of the force on the x-axis, so it is very simple. If you understand the vector operation in mathematics,
is a very simple problem.
the second question is actually that sentence, the projection of the moment of the space force on the x-axis is equal to the moment of the force on the x-axis, so it is very simple. If you understand the vector operation in mathematics,
is a very simple problem.
6. In the plane problem, if the force F and the center of moment o are in the same plane, the algebraic quantity mo (f) is enough to generalize all the elements of the moment of the force to point o. But in the space problem, because the plane determined by each force and the moment center O may be different, the orientation of each force making the rigid body rotate around the same point may also be different. In order to reflect the orientation of rotation effect, the moment of force to point must be expressed by vector.
7. (1) (2) the four fingers first point to the direction of arm R (x-axis), then bend to the direction of force F (Y-axis) (the bending direction of the four fingers must point to the direction of F), and the direction of thumb along the axis (Z-axis) is the direction of moment
if the direction of thumb along the axis is the positive direction of Z axis, the moment is positive
if the direction of the thumb along the axis is the negative direction of the Z axis, the moment is negative.
if the direction of thumb along the axis is the positive direction of Z axis, the moment is positive
if the direction of the thumb along the axis is the negative direction of the Z axis, the moment is negative.
8.
The moment is a vector, but its component in a certain direction is an algebraic quantity
The unit of torque is Newton meter. The Greek letter is tau. The concept of moment originated from Archimedes' study of lever. Rotational torque is also called torque or torque. Torque can change the rotational motion of an object. Pushing or pulling involves forces, while torsion involves moments. The moment is equal to the cross proct of the radial vector and the applied force 
extended data
the properties of moment
1. The moment of force F to point O is not only determined by the force, but also related to the position of moment center. The moment varies with the position of the moment center
When the force is zero or the arm of force is zero, the moment is zero When the force moves along its action line, because the magnitude, direction and arm of the force do not change, the moment does not change The algebraic sum of the moments of two mutually balanced forces at the same point is equal to zero9.
Difference 1. Different meaning
moment of force: the physical quantity of the rotation effect of force on an object
force is the action of an object on an object
2. Different units The unit of torque is n · M Unit of force: n The differences between them are as follows:
3
The calculation of moment can be obtained by the cross proct of radial vector and force
the dimension of force is mlt-2, where m, l and T are the dimensions of mass, length and time respectively. In dynamics, it is equal to the proct of the mass and acceleration of the object
extended data:
forces can be divided into two categories. One is named according to the nature of forces, such as gravity, elastic force, friction force, molecular force, electric power, magnetic force, etc; The other is named according to the effect of force, such as tension, pressure, supporting force, power, resistance, etc
The force is a vector and the international unit is Newton The interaction offorces is mutual
effect of force:
1
2
Three elements of force:1, size
2
3
10. What's the difference between torque, torque and torque
in physics, torque refers to the tendency that the force makes the object rotate around the rotation axis or fulcrum. Moment, the physical quantity of the rotation effect of the force on the object, can be divided into the moment of the force on the axis and the moment of the force on the point. Rotational torque is also called torque or torque
where l is the distance vector from the axis of rotation to the point of application and F is the vector force. The moment is also a vector. The unit of moment is Newton meter
the concept of moment can be seen everywhere in our daily life, from the seesaw we played when we were young to the famous saying of Archimedes - "give me a fulcrum, I will pry the whole earth", all of which embody the meaning of moment. Similarly, torque is everywhere in the car, but through a series of transmission shaft rotation, the torque here is called torque. The size of torque directly affects the work efficiency of power output, energy consumption, even operation life and safety performance and other factors
the difference between torque and torque:
they cover different ranges. The range of torque is broader. All the results of force multiplied by arm of force can be called torque, but torque generally refers to the torque of rotating objects. For example, when a wheel rotates, the proct of ground friction and wheel radius is generally called torque, but it is also a kind of torque. When a beer bottle is opened with a bottle driver, it is generally called torque, not torque
the difference between torque and torque:
the couple or torque that makes the machine elements rotate (including the tendency to rotate) is called the rotating torque, which is short for torque. Any element under the action of torque must proce some degree of torsional deformation (including elastic deformation and plastic deformation). Therefore, it is customary to call the rotational torque torsional torque, or torque for short. They can be mixed in any field, but torque is more commonly used in engineering technology< In fact, torque, torque and torque are the same in motors. Generally, in the same article or book, only one of the above three nouns is used, and it is rare to see two or more nouns used at the same time. Although these three words are used in different occasions, they all refer to the driving "moment" generated by the rotor winding in the motor, which can be used to drive the mechanical load. The so-called "moment" refers to the proct of the force and the distance between the fulcrum and the direction of the force.
in physics, torque refers to the tendency that the force makes the object rotate around the rotation axis or fulcrum. Moment, the physical quantity of the rotation effect of the force on the object, can be divided into the moment of the force on the axis and the moment of the force on the point. Rotational torque is also called torque or torque
where l is the distance vector from the axis of rotation to the point of application and F is the vector force. The moment is also a vector. The unit of moment is Newton meter
the concept of moment can be seen everywhere in our daily life, from the seesaw we played when we were young to the famous saying of Archimedes - "give me a fulcrum, I will pry the whole earth", all of which embody the meaning of moment. Similarly, torque is everywhere in the car, but through a series of transmission shaft rotation, the torque here is called torque. The size of torque directly affects the work efficiency of power output, energy consumption, even operation life and safety performance and other factors
the difference between torque and torque:
they cover different ranges. The range of torque is broader. All the results of force multiplied by arm of force can be called torque, but torque generally refers to the torque of rotating objects. For example, when a wheel rotates, the proct of ground friction and wheel radius is generally called torque, but it is also a kind of torque. When a beer bottle is opened with a bottle driver, it is generally called torque, not torque
the difference between torque and torque:
the couple or torque that makes the machine elements rotate (including the tendency to rotate) is called the rotating torque, which is short for torque. Any element under the action of torque must proce some degree of torsional deformation (including elastic deformation and plastic deformation). Therefore, it is customary to call the rotational torque torsional torque, or torque for short. They can be mixed in any field, but torque is more commonly used in engineering technology< In fact, torque, torque and torque are the same in motors. Generally, in the same article or book, only one of the above three nouns is used, and it is rare to see two or more nouns used at the same time. Although these three words are used in different occasions, they all refer to the driving "moment" generated by the rotor winding in the motor, which can be used to drive the mechanical load. The so-called "moment" refers to the proct of the force and the distance between the fulcrum and the direction of the force.
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