Torque is not a force. Torque, also known as Moment of force, (denoted with (tau)) the is ‘turning effect’ of a force.
Definition
Just as linear force results in acceleration, torque results in angular momentum (but you don’t need to know that). It is what causes object to achieve rotary motion. Torque requires a fixed pivot point, and an ‘arm’ that can be rotated. Note that this is the classic way to represent torque; not every example is as simple.
Technically, torque is a vector. However, I have yet to find a VCAA question that has to do with the vector nature of torque, so we can assume that torque only acts in 2 directions: clockwise and anti-clockwise.
Calculating Torque
- = Torque (in Newton-metres, Nm)
- = Force (in Newtons, N)
- = Distance from pivot to force point or length of lever arm (in metres, m)
Note: This only applies when the force is perpendicular to the lever arm. If it is not, use:
- = Angle between force and lever arm
Applications
Torque is used extensively in levers, as well as linkages. Torque can be found everywhere, from the grip of tyres in a car to the strength of a can-opener.