Moment in physics refers to the tendency of an object to rotate around a rotation axis or fulcrum under force. The unit of torque is Newton meters. The Greek letter τ stands for torque. The concept of torque originated from Archimedes' research on lever. Rotational torque is also called torque or torque. Moment can make an object change its rotational motion. Pushing or dragging involves force, while twisting involves moment. The moment is equal to the cross product of the radial vector and the acting force.

Extended data

1. The moment of force F to point O depends not only on the magnitude of the force, but also on the position of the moment center. The moment varies with the position of the moment center;

2. When the force is zero or the arm is zero, the moment is zero;

3. When the force moves along the line of action, the moment remains unchanged, because the magnitude, direction and arm of the force have not changed.

4. The algebraic sum of the moments of two forces that are balanced at the same point is equal to zero.

Unit transformation

The dimension of torque is distance multiplied by force; According to the international system of units, the unit of torque is Newton meters. Although the order of Newton and Rice can be changed mathematically. BIPM (International Bureau of Weights and Measures) sets this order of magnitude to Newton meters instead of meters Newton.

international system of units (SI)

According to the international system of units, the unit of energy and work is joule, which is defined as 1 Newton meter. However, Joule is not a unit of moment. Because energy is a scalar of the product distance of force points; Moment is the pseudo vector of distance cross product force. Of course, the same dimension is not just a coincidence; It takes 2 *π joules of energy to make the torque of 1 Newton-meter rotate for a whole turn.

debate

In fact, the relationship between torque and energy is the product of energy and a logarithmic vector 2π[lnK], that is, t=2πQ[lnK], and the direction of [lnK] is perpendicular to the action surface. So there is nothing wrong with using joules as a unit. When doing circular motion, K=e, so it takes 2 *π joules of energy to make a complete rotation, resulting in a torque of 1 Newton meters.

Reference torque _ Baidu Encyclopedia?