SIMPLIFIED: "7.5: Torque"

Link to article: https://phys.libretexts.org/Courses/University_of_California_Davis/UCD%3A_Physics_7B_-_General_Physics/7%3A_Momentum/7.5%3A_Torque 

Note: The image above was taken from the original article.

I personally feel like the word “torque” sounds quite scary. Essentially, torque is the same thing as a force, but in rotational form. Think about it like this: if you apply a force to something, you will make that object accelerate. If you apply torque to something, you will cause something to rotate.

In a nutshell, the torque is: Torque = Force * radius (there is a sin of theta component to it but I am explaining torque in a very introductory way so we will assume that all forces are perpendicular). When calculating torque, you will plug in the magnitude of force you are applying. The radius is the distance from the rotational axis to the place where a force was exerted. The rotational axis is essentially just the pivot, or the place where something is rotating on. The easiest example is a door. A door rotates around a hinge, and that hinge is the axis of rotation. If you think about it, if you want to swing open a door, you will need to apply more force if you push the door right next to the hinge. This is because the distance from the rotational axis to the place where you are exerting the force is very small, meaning to apply sufficient torque to rotate the door, you need to make up for the small distance with a larger force. On the other hand, it is easier to rotate a door if you push near the doorknob. This is because the doorknob is very far away from the rotational axis, so the radius variable in the equation increases. 

Now, there are other equations to calculate torque that involve the moment of inertia and angular acceleration. These ideas are not going to be covered in this specific simplified article that we have written for you. It is important to mention that the unit for torque is the Newton Meter. This is because the unit for force is the newton, and the unit for the radius/distance is the meter. Since we are multiplying these two variables together, the unit for torque is ultimately Newton-Meter.