Work power & energy:
Work: Work is 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 distance (d)
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?
Power: The rate of doing work is known as power.
i.e. Power = Work done/Time taken
The power is expressed in joule/sec. or watt (1 watt = 1 Newton metre/second)
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.
Energy: Capacity 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.
1 Calorie = 4.18 joules
The energy can be in transition or is stored in the system boundaries.
Examples of energy stored in the system are
- Potential energy
- Kinetic energy
- Internal energy
Potential energy (PE): The energy of a body by virtue of its height is known as potential energy.
PE = mgh
Where m is the mass of body, g is gravitational acceleration and h is the height through which body is lifted.
Kinetic energy (KE): The kinetic of a body by virtue of its velocity is known as Kinetic energy.
KE = ½ mv2
Where m is the mass of the body and v is the velocity with which it is moving.
Internal Energy: The balance energy is known as the internal energy.
Heat and work are the forms of energy in transition.