What is and how to calculate the torque: the guide with the formula and the unit of measurement to calculate the moment of a force in physics.
Torque refers to the movement of a force . It is a quantity inherent in rotational dynamics and can be considered as the rotational equivalent of the concept of force.
The twisting motion is that quantity that combines the intensity of a force, to which we give the name of F, and the distance from the fulcrum or axis of rotation which for convenience we will call r.
The formula we need to apply to find the torque is: M = r * F.
The unit of measurement used for torque is Newton per meter (Nm). This equation is valid only if the force is applied to the axis of rotation according to its tangent. It is precisely the tangential component that produces the twisting movement.
Thanks to this, we can break down the force into its components and therefore we can give the general definition of torque even when its tangent forms an angle other than 90° (with this value we speak of maximum torque).
Torque also involves a change in the angular motion of an object, thus also causing angular acceleration. After considering the theoretical implications, we are ready to see how to calculate torque .
Practical example
Suppose we need to unscrew a bolt. Using a wrench will certainly make it less difficult to unscrew it, since we will be exerting a force at the end of our tool.
If we exert a force as far as possible from the fulcrum around which the object rotates, the less effort we will make.
If we think of the bolt as our fulcrum “F” and our wrench as the distance from the fulcrum “r”, where we apply our force, the relationship explained previously will become clearer.
How to understand if the moment is positive or negative
Torque, being a vector, can be negative or positive, so it is necessary to consider the direction in which the force is applied with respect to the axis of rotation of the object and the effect that this force will have on the rotation.
If the force tends to increase the speed of rotation in a counterclockwise direction, the moment is considered positive; if, instead, it tends to decrease the speed of rotation or to make it rotate in a clockwise direction, the moment is negative.
Conclusions
We can conclude with a very interesting observation. Once we have found the torque, we can also determine the angular acceleration of a system.
Angular acceleration is directly proportional to torque and inversely proportional to inertia.
Finally, let us remember that, even if we have calculated the torque with a particular case of a mass, this relation is valid for any object.
