WORK, POWER & ENERY

When force acting on a body produces a change in the position of the body, work is said to be done by the force. Work done on an object is defined as the magnitude of the force multiplied by the distance moved by the object in the direction of the applied force.

The Unit of Work Is Joule:

1 Joule = 1 Newton 1 Meter.

Work done on an object by a force would be zero if the displacement of the object is zero.

• Power is defined as the rate of doing work. Power = (work done) / (time taken). The SI unit of power is watt. 1 W = 1 Joule/second. The unit of power is also horsepower. It is the power of an agent which can work at the rate of 550-foot pounds per second- or 33,000-foot pounds per minute.

• An object having capability to do work is said to possess energy. Energy has the same unit as that of work.

• An object in motion possesses what is known as the kinetic energy of the object. An object of mass, m moving with velocity v has a kinetic energy of

• The energy possessed by a body due to its change in position or shape is called the potential energy. The gravitational potential energy of an object of mass, m raised through a height, h from the earth’s surface is given by mgh.

• According to the LAW OF CONSERVATION OF ENERGY, energy can only be transformed from one form to another; it can neither be created nor destroyed. The total energy before and after the transformation always remains constant.