Definition

Work:

1. Work is said to be done when a force acting on a body moves it in the direction of the force.
• Work = FS
• SI unit of work is the joule (J).
Definition

Energy:

1. When we say that a body has energy, we mean that it can do work. SI unit of energy is also joule, the same as work.

Definition

Forms of Energy:

Energy exists in various forms such as mechanical energy, heat energy, light energy, sound energy, electrical energy, chemical energy, nuclear energy, etc. Energy from one form can be transformed into another.

Definition

Kinetic energy:

The energy possessed by a body due to its motion is called kinetic energy.

Definition

Potential energy:

The energy possessed by a body due to its position is called potential energy.

Definition

Law of conservation of energy:

Energy cannot be created nor destroyed, but it can be converted from one form to another.

Definition

Einstein Equation:

Einstein predicted the interconversion of matter and energy by the equation \$E = mc^{2}\$.

Definition

Nonrenewable resources:

Fossil fuels are known as nonrenewable resources because it took millions of years for them to attain their present form.

Definition

Efficiency:

The ratio of the useful work done by a device or machine to the total energy taken up by it is called its efficiency.

Definition

Power:

Power is defined as the rate of doing work.

Definition

Watt:

1. The power of a body is one watt which is doing work at the rate of one joule per second.