said to be done if we apply force on a body and the body
moves in the direction of force applied. The work can be
calculated by the product of the force and the distance
through which a body moves.
i.e. Work done = Force (F) X
The work done is expressed in joule. Which is defined as
the work done when a force of 1 newton is applied on a body
through a distance of 1 metre?
of doing work is known as power.
i.e. Power = Work done/Time
The power is expressed in joule/sec. or watt (1 watt =
The bigger unit of power such as Horse power and Kilowatt
are also used. Where 1 Horse power = 746 watts and 1
Kilowatt = 1000 watts.
to do work is called energy. It has the same unit as that of
work i.e. joule. It can also be expressed in calories.
= 4.18 joules
The energy can be in transition or is stored in the system
Examples of energy stored in the system are
of a body by virtue of its height is known as potential
PE = mgh
Where m is the mass of body, g is gravitational
acceleration and h is the height through which body is
The kinetic of a body by virtue of its velocity is known as
KE = ½ mv2
Where m is the mass of the body and v is the velocity with
which it is moving.
The balance energy is known as the internal energy.
are the forms of energy in transition.