WORK AND ENERGY (FOR CLASS 8)

WORK: The action for producing the displacement by exerting force on object is called work.

• Work done on object depends on

a) displacement
b) force exerted on object

• work= force x displacement in direction of force.
• SI unit of work is Joule.

ENERGY: Capacity of doing work in objects is called energy.

• SI unit of energy is Joule, as work and energy are equivalent to each other.
• There are various types of energy. eg. Mechanical energy, Heat energy, Chemical energy, Light Energy, Chemical energy, Magnetic energy, Sound energy, Atomic energy.

Mechanical Energy: Mechanical Energy is combination of Kinetic Energy and Potential Energy.

1. Kinetic Energy:(KE): The capacity of doing work due to an object is in motion is called Kinetic Energy.
2. Potential Energy:(PE): When we make change in position or shape of an object, then mechanical energy stored in it is called potential energy.

Heat Energy: Energy stored in burning objects of hot objects is called Heat Energy.
Chemical Energy: Energy stored in fuels is called Chemical Energy.
Light Energy: Energy stored into light of sun or bulb, etc is called Light Energy

Electric Energy: Energy obtained due to change in motion is called Electric Energy.
Magnetic Energy: Energy stored in magnetic field is called Magnetic Energy.
Sound energy: Energy stored in sound (vibration) is called Sound Energy.
Atomic Energy: Energy obtained from nuclear fusion or fission is called Atomic Energy.