CBSE Class 9 Science Work and Energy Exam Notes. Please refer to the examination notes which you can use for preparing and revising for exams. These notes will help you to revise the concepts quickly and get good marks.
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 meter in its own direction, then the work done is known as 1 joule.
Ex.1How much work is done by a force of 10N in moving an object through a distance of 1 m in the direction of the force ?
Sol The work done is calculated by using the formula:
W = F × S
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