What is Energy?
Energy can be defined as the capacity to do work.

Types of Energy


Mechanical Energy: - By definition mechanical energy is the sum of Kinetic energy(K.E) and Potential energy(P.E).

Mechanical energy = Kinetic Energy + Potential Energy

Kinetic Energy: - Kinetic energy is the energy due to a body’s motion.

K.E = 1/2 mass × velocity²

Potential Energy: - Potential Energy is energy due to a body’s position or condition.

P.E = mass × gravity × height

Law of Conservation of mechanical energy
In a system where only forces associated with potential energy are acting (gravitational/ elastic), the sum of the Kinetic and Potential energies is constant.

K.E + P.E = Constant

These conditions exist for any object rising of falling above the earth’s surface:

1. For a body that is rising:

Loss in K.E = Gain in P.E

     2.  For a body falling towards the earth:

Loss in P.E = Gain in K.E