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*What is the Torque – Basic Concepts of Mechanics*

Torque is a measure of how much a force acting on an object causes that object to rotate. It is a force that you use to rotate or turn things.

**Relationship between torque and force : **

Most of the students confused in between force and torque, torque is different term than force. Force is ability to do work. Force can be present without torque but torque cannot be present without force. Force is a unit used to describe an intensity in translational motion, whereas torque is a unit of intensity in rotational motion

**Why do we need to know this?**

Understanding the relationship between torque, power and engine speed is vital in automotive engineering, concerned as it is with transmitting power from the engine through the drive train to the wheels. The gearing of the drive train must be chosen appropriately to make the most of the motor’s torque characteristics. Steam engines and electric motors tend to produce maximum torque at or around zero rpm, with the torque diminishing as rotational speed rises (due to increasing friction and other constraints). Therefore, these types of engines usually have quite different types of drive trains from internal combustion engines. Torque is also the easiest way to explain mechanical advantage in just about every simple machine

**Torque in ****everyday**** life -Torque Examples : **

Tightening the lug nuts on the wheels of your car is a good example of torque. When we use a wrench, we apply a turning force to the handle. This turning force turns the lug nut. The wrench acts like a lever. If the handle on the wrench is longer, the less pushing force required to tighten the nut. A wrench with a shorter handle is harder to turn. It means the longer the handle, the more force it applies, and the easier it is to turn the nut.

**Torque equation**

*How to Calculate torque : *

T= F ×r × sinӨ

Where,

T= torque

F= linear Force

r= distance from axis of rotation of

object to where force is applied

Ө= angle between F and r

# What is the SI unit for torque?

Torque is the product of Force Applied and the Perpendicular distance (or say Radius) from the Applied Force and the centre of the gear or the fulcrum.

It is given by, T= Force x Perpendicular Distance

The SI Unit for Force is Newton(N) and for Distance is Meter(m).

Therefore, the SI Unit for Torque is “Nm”