This note provides us an information about energy .Energy of a body is defined as the capacity to do work. It is a scalar quantity. Mechanical energy is one of the energy. There are two types of mechanical energy i.e. kinetic energy and potential energy.
The energy possessed by the body due to its motion is called kinetic energy.
According to the principle of conservation of energy , energy of an isolated system is constant. It is neither be created nor be destroyed but it transforms from one type to another type. When an object falls on the ground from the certain height, its kinetic energy is converted into another form of energy such as sound energy, heat energy, light energy etc.
Collision is the mutual interaction between two particles for a short interval of time so that their momentum and kinetic energy may change. Collision is an isolated event in which two or more colliding bodies exert relatively strong forces on each other for a relatively short time. Actual physical contact is not necessary for a collision.
The collision in which momentum is conserved but K.E is not conserved called inelastic collision. In this collision, the nature of force is non conservative. In inelastic collision, kinetic energy is lost in the form of heat energy, sound energy, light energy etc.