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The concept of torque

The force required to rotate an object around an axis is measured as torque.In linear kinematics, force causes an object to accelerate; in angular kinematics, torque causes an object to accelerate.It is measured as a vector. The torque vector's direction is determined by the force acting on the axis.

Torque is the rotational equivalent of linear force in physics and mechanics. It’s also known as the moment, moment of force, rotational force, or turning effect, depending on the subject of research. It refers to a force’s ability to produce a change in a body’s rotational motion. The concept was born out of Archimedes’ research into the usage of levers. A torque is a twist of an object around a certain axis, much like a linear force is a push or a pull.Torque is the product of the force’s quantity and the perpendicular distance between the force’s line of action and the axis of rotation.

Torque is usually denoted by the letter , which is the lowercase Greek letter ‘tau’. When the term “moment of force” is used, it is usually abbreviated as M.

Torque can be either static or dynamic:

The term “static torque” refers to a torque that does not create an angular acceleration. Because the door does not rotate on its hinges despite the force applied, someone pushing on it applies a static torque to it. Because they are not accelerating, someone pedalling a bicycle at a steady speed is likewise applying a static torque.

A dynamic torque is carried by the drive shaft of a racing car accelerating from the start line because it must produce an angular acceleration of the wheels provided that the car is accelerating along the course.

The vocabulary used to describe torque can be a bit perplexing. Engineers frequently use the terms moment and moment of force interchangeably.The moment arm refers to the radius at which the force acts.

Torque Formula:


= Frsinθ

stands for Torque.

F stands for linear force.

r is the distance measured from the rotation axis to the point where linear force is applied.

θ = the angle formed between F and r

In this formula, sinθ has no units, r has metres (m) as units, and F has Newtons as units (N). When these are added together, one can see that a Newton-metre is the unit of force (Nm).

Direction of Torque:

The right hand grip rule is used to determine the direction of the torque vector. The torque vector points in the direction of the thumb when a hand is curled around the axis of rotation with the fingers pointing in the force direction.

In rotational kinematics, what role does torque play?

Torque replaces force in linear kinematics in rotational kinematics. Newton’s 2nd law of motion (F=ma) has a direct equivalence

= I

The angular acceleration is denoted by . It is the rotational inertia of a spinning system, which is determined by the system’s mass distribution. The greater the I, the more difficult it is for an object to get angular acceleration. 

What is the best way to enhance or decrease torque?

To suit various applications, it is frequently required to increase or decrease the torque produced by a motor. Remember that a lever’s length can increase or decrease the force applied to an object at the expense of the distance the lever must be pushed. Similarly, gearing can be used to enhance or reduce the torque produced by a motor. A proportional drop in rotational speed is associated with an increase in torque. The interaction of two gear teeth can be compared to the interaction of two levers. In cars with combustion engines, the use of adjustable gearing is required for good performance.

At any given engine rotational speed, adjustable gearing permits enough torque to be transmitted to the wheels. Humans are unable to pedal at a cadence high enough to attain a practical speed when driving a wheel directly, hence bicycles require gearing. In vehicles powered by steam engines or electric motors, adjustable gearing is not usually required. High torque is provided at low speeds in both circumstances and remains reasonably steady throughout a large range of speeds.


Torque is the propensity of a force to turn or twist in physics. Torque is described using a variety of terminologies, including moment and moment of force. A see-saw or an automotive engine are two examples of real-life torque applications. So the next time you go out, look for objects that work on the torque concept. Torque is often caused by many forces acting on an object in the real world. The sum of the individual torques is the net torque. There is no net torque on the object while it is in rotational equilibrium. Individual torques may exist, but they all sum up to zero and cancel each other out.


Frequently asked questions

Get answers to the most common queries related to the CBSE 11th Examination Preparation.

When it comes to torque and moment, what's the difference?

Ans : Torque is a type of Moment that has to do with the axis of rotation that drives the rotation....Read full

Is there any torque energy?

Ans : Torque is not a kind of energy.

What is the difference between torque and force?

Ans : In rotational mechanics, torque is the opposite of force. Torque is the ability of a force to...Read full

What are some real-life examples of torque?

Ans : Torque can be seen in the opening of a bottle cap or the turning of a steering wheel....Read full