Work and Energy
1. Work
Work is said to be done when a force applied on an object displaces it in the direction of the
force.
If there is no displacement, no work is done.
Example:
Pushing a wall does not do any work because the wall does not move.
2. Mathematical Expression of Work
Unit of work: Joule (J)
1 joule = work done when a force of 1 N displaces an object by 1 m in the direction of force.
3. Types of Work
(a) Positive Work
When force and displacement are in the same direction.
Example:
A person pulling a trolley forward.
(b) Negative Work
When force and displacement are in opposite directions.
1. Work
Work is said to be done when a force applied on an object displaces it in the direction of the
force.
If there is no displacement, no work is done.
Example:
Pushing a wall does not do any work because the wall does not move.
2. Mathematical Expression of Work
Unit of work: Joule (J)
1 joule = work done when a force of 1 N displaces an object by 1 m in the direction of force.
3. Types of Work
(a) Positive Work
When force and displacement are in the same direction.
Example:
A person pulling a trolley forward.
(b) Negative Work
When force and displacement are in opposite directions.
