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1. Work is said to be done if a force is applied on the object and it is displaced from its original position.
2. Three things are necessary for the performance of work:
- There must be an applied force F.
- There must be a displacement x.
- The force must have a component along the displacement
W = Fd cos θ
where d is the displacement of an object.
θ is the angle between the force and the displacement.
4. If displacement is along the direction of work i.e. θ = 0°
W = Fd
5. If displacement is opposite to the force i.e. θ = 180°
W = -Fd
6. if the displacement is perpendicular to the force (i.e. θ = 90°), then work done is zero.
7. Work done on an object by a force would be zero if the displacement of the object is zero.
8. Work is a scalar quantity.
9. Unit of work is Joule (J).
10. 1 Joule = 1 newton × 1 metre = 1 Nm
11. One Joule of work is to be done on an object when a force of one newton displaces it by one metre along the time of action of the force.