Mechanics

# Moment or Torque of a Force

When changing a car tire, we use a wrench (L-shaped wheel wrench) that, in contact with the nut that holds the wheel and being under the action of the force applied by us (resulting force/decomposition must be perpendicular to the arm key), produces the rotation of the nut, allowing us to remove the wheel and change the tire.

Removing the nut with the mentioned wrench becomes easier as we increase the “arm” of the wrench, requiring less force to be able to perform the same work.

Actions that we perform in everyday life, such as opening a door, changing a car tire using a “wheel wrench”, among other circumstances, will require less force from us if the “lever” arm is increased.

The physical quantity associated with the rotational movement of a given body due to the action of a force is called torque, that is, torque is defined as the product of the force f applied in relation to a given point (pole) by the distance separating it from the point of application of that force to the point (pole).
We will interpret the mathematical expression T = Fd in which T will be positive if the rotation occurs clockwise, because if it occurs counterclockwise, it will be negative. From figure 1.

This is the concept that justifies why the door handle of your house is far from the hinge (pole), because if it were close, we would need more force to open or close it.
If you still have doubts about the applications of this quantity; try to open a gate applying the force very close to the hinges and you will see the result.