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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)

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NTSE Physics (Class X)

• Electricity
• Magnetic Effect of Curent
• Light Reflection
• Light Refraction
• Human Eye & Colourful World
• Source of Energy
• Motion

NTSE Physics (Class IX)

• Force & laws of motion
• Work and Energy
• Gravitation
• Sound

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