Principle of Conservation of Energy

Principle of Conservation of Energy

Energy can neither be created nor can be destroyed. Only energy can be transformed from one form to another form. Whenever energy is utilized in one form, equal amount of energy is produced in other form. Hence total energy of the universe always remains the same. This is called the principle of conservation of energy.

Some Equipments used to Transform Energy

S. No.	Equipment	Energy Transformed
1.	Dynamo	Mechanical energy into electrical energy.
2.	Candle	Chemical energy into light and heat energy.
3.	Microphone	Sound energy into electrical energy.
4.	Loud Speaker	Electrical energy into sound energy.
5.	Solar cell	Solar energy into electrical energy.
6.	Tube light	Electrical energy into  light energy
7.	Electric Bulb	Electrical energy into light and heat energy.
8.	Battery	Chemical energy into electrical energy.
9.	Electric motor	Electrical energy into mechanical energy.
10.	sitar	Mechanical energy into sound energy.

Relation between Momentum and kinetic Energy

K.E = p²/ 2m where p = momentum = mv

Clearly when momentum is doubled, kinetic energy becomes four times.

Power: rate of ding work is called power.

It an agent does W work in time t , then power of agent = W/ t

SI unit of power is watt named as a respect to the scientist James Watt.

                Watt = joule /sec.

                 1 k W= 10³ watt

                 1 MW = 10⁶ watt

 Horse power is a practical unit of power. 1 H. P. = 746 watt.

                 1 watt second = 1 watt x 12 second = 1 joule.

                1 watt hour (Wh) = 3600 joule

                1 kilowatt hour (kWh) = 3.6 x 10 ⁶ joule.

W, Kw,MW & H.P. are units of power.

Ws, WH, k Wh are units of work and energy.