Question

What is mechanical energy? Explain in detail.

Answer 1

Hint: Energy is defined as the ability to do work. It has the same units as that of work and the SI unit of energy is Joule (J). Energy is defined as the ability to do work. It has the same units as that of work and the SI unit of energy is Joule (J). The term mechanical energy arises from the Work-Energy theorem which states that work and energy are interconvertible. From this theorem, we can arrive at the definition of mechanical energy.

Complete step-by-step answer:
We know from the definition of energy (as stated above), that energy is related to the work being done. There is a theorem which relates these quantities known as the Work Energy theorem, which states that the net work done on an object is equal to the change in kinetic energy of the system.
Thus, we see that when work is done on an object, it gets converted to an increase in the kinetic energy of the system and this does not manifest from nowhere. The potential energy inside the body starts decreasing which leads to the increase in the kinetic energy, thus obeying the law of conservation of energy which states that energy can neither be created nor destroyed.
This energy that is acquired by the objects when work is done on them, is called mechanical energy.
The word mechanical is associated with motion. The energy possessed by an object by virtue of its position is potential energy and the same energy gets converted into kinetic energy when set into motion or when work is done on it. The net energy at any point i.e. the sum of the kinetic and potential energy and is equal to the mechanical energy.
Mechanical Energy = Kinetic Energy + Potential Energy
The purpose of having mechanical energy in a body is to do work. The work is done by a body at the expense of mechanical energy.
For example, when we eat food, the chemical energy in the food gets converted to thermal energy and thus, mechanical energy. The mechanical energy is spent by us when we move because we are doing work. When we do the work, the mechanical energy, which can be thought of as our bank or credit balance, is being spent to perform the work, which can be thought of as a bank transaction.

Note: Mechanical energy is highly effective and convertible easily to other forms of energy viz. thermal energy, electric energy etc. making the study of the mechanical energy classified into a vast discipline of engineering known as Mechanical Engineering. This branch of Engineering mainly, deals with conversion of energy from mechanical to other forms through objects known as machines.