3. Work and Energy
Work and its Unit
Definition : In our daily life "work" implies an activity resulting in muscular or mental exertion. However, in physics the term 'work' is used in a specific sense involves the displacement of a particle or body under the action of a force. "work is said to be done when the point of application of a force moves.
Work done in moving a body is equal to the product of force exerted on the body and the distance moved by the body in the direction of force.
Work = Force × Distance moved in the direction of force.
The work done by a force on a body depends on two factors :
(i) Magnitude of the force, and
(ii) Distance through which the body moves (in the direction of force)
Unit of Work
When a force of 1 newton moves a body through a distance of 1 metre in its own direction, then the work done is known as 1 joule.
Work = Force × Displacement
1 joule = 1 N × 1 m
or 1 J = 1 Nm (In SI unit)