Answer :

The word energy is very often USED in our daily life, but in science we give it a definite and precise meaning.

An EXAMPLE is considered for better understanding :

When a FAST moving cricket ball hits a stationary wicket, the wicket is thrown away. SIMILARLY, an object when raised to a certain height gets the capability to do work.

So we can say that

AN OBJECT HAVING CAPABILITY TO DO WORK IS SAID TO POSSESS ENERGY.

=> S.I Unit of Energy --

Energy has the same unit as that of work, that is Joules ( j ).

FORMS OF ENERGY --

1. Kinetic Energy --

The energy possessed by an object by virtue of its motion is called Kinetic Energy.

Examples -

• Moving vehicle like CARS,buses,trucks etc.
• A moving bullet possesses kinetic energy, due to which, it can pierce even a human body.

Expression of Kinetic Energy =

where, m = mass, v = velocity.

2. Potential Energy --

Potential energy is the energy possessed by an object by virtue of its position or shape and size or change thereof.

Examples --

• A wound spring of a toy car or mechanical watch has potential energy due to change in its shape.
• The stretched rubber string has potential energy due to change in its shape and size.

Expression of Potential Energy = mgh
where m = mass, g = gravity and h = height

=> POTENTIAL ENERGY CONSISTS OF TWO TYPES -

* Gravitational Potential Energy
* Elastic Potential Energy.

We see many forms of Energy around us

For example
• A moving fan consist of Kinetic Energy.
• A person while cycling consist of Mechanical Energy.


HOPE IT WOULD HELP YOU