Energy

Energy

Energy is the capacity to do work. Every activity that we perform — whether it is walking, running, lifting objects, or even thinking — requires energy. All machines, whether simple or complex, need energy to function.

Forms of Energy

Energy exists in various forms. Some common types include:

• Kinetic Energy: Energy possessed by a body due to its motion. Example: A moving car.
• Potential Energy: Energy that a body has because of its position or arrangement is known as potential energy. Example: Water stored in a dam.
• Thermal Energy: Related to the temperature of a substance; produced by movement of particles within matter.
• Chemical Energy: Stored in the bonds of chemical compounds, like food and fuel.
• Electrical Energy: Produced by the movement of electrons; used to run electrical appliances.
• Sound Energy: Produced by vibrating objects and travels through a medium.
• Light (Radiant) Energy: Comes from the sun and other luminous sources; necessary for vision and photosynthesis.

Unit of Energy

In the SI system, energy is measured in joules (J). Additional commonly used units are kilojoule (kJ), calorie, and kilowatt-hour (kWh).

Kinetic Energy

Kinetic energy is given by the formula:

( KE = frac{1}{2}mv^2 )

Where,

• m = mass of the object (kg)
• v = velocity of the object (m/s)

Potential Energy

The formula used to calculate potential energy is:

( PE = mgh )

Where,

• m = mass of the object (kg)
• g = acceleration due to gravity (9.8 m/s²)
• h = height of the object (m)

Law of Conservation of Energy

This law states that energy can neither be created nor destroyed. It can only be transformed from one form to another, but the total energy remains constant in an isolated system.

Energy is essential for performing work and sustaining life. Understanding its forms and transformations helps us make better use of resources and develop sustainable solutions for the future.