Work And Energy

Work:- Work done by the force is defined as dot product of force and displacement vector
- For constant Force

where F is the force vector and s is displacement Vector
-For variable Force


or W=∫F.ds

-It is a scalar quantity

Conservative And Non Conservative Forces
-If the workdone by the force in a closed path is zero,Then it is called conservative Force
-If the workdone by the force in a closed path is not zero,Then it is called non conservative Force
-Conservative Forces are gravtitional ,electrical force
-Non Conservative Forces are friction

Kinetic Energy:-It is the energy possesed by the body in motion
-it is defined as
- Networkdone by the external force is equal to the change in the kinetic energy of the system

Potential Energy:
-It is the kind of energy possesed due to configuration of the system
-It is due to conservative force
-it is defined as

Where F is the conservative force


For gravtitional Force
Change in Potential Energy =mgh

where h is the height between the two points

Mechanical Energy is defined as

Law Of conservation of Energy

In absence of external forces,intenal forces being conservative ,total energy of the system remains constant.

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