NCERT Gist: Work and Energy | Additional Study Material for UPSC PDF Download

- Two conditions need to be satisfied for work to be done: (i) a force should act on an object, and (ii) the object must be displaced.
- Work done by a force acting on an object is equal to the magnitude of the force multiplied by the distance moved in the direction of the force.
- Work has only magnitude and no direction.
- Unit of work is newton metre (N m) or joule (J).
- Work done is negative when the force acts opposite to the direction of displacement.
- Work done is positive when the force is in the direction of displacement.
- An object having a capability to do work is said to possess energy.
- The object which does the work loses energy and the object on which the work is done gains energy.
- Objects in motion possess energy which is known as kinetic energy.
- The kinetic energy of an object increases with its speed.
- The kinetic energy of a body moving with a certain velocity is equal to the work done on it to make it acquire that velocity.
- Kinetic energy of an object in the form of an equation.
- The potential energy possessed by the object is the energy present in it by virtue of its position or configuration.
- The potential energy of an object at a height depends on the ground level or the zero level you choose.
- An object in a given position can have a certain potential energy with respect to one level and a different value of potential energy with respect to another level.
- The sum of the potential energy and kinetic energy of the object would be the same at all points.
- The sum of kinetic energy and potential energy of an object is its total mechanical energy.