Key notes on What is Mechanical Energy

Every object around us possesses mechanical energy. Whether it is a hand that swings the tennis racket or a rotating fan in our living room, they all move due to mechanical energy. All the simple and complex systems that exert force – use mechanical energy to get the work done. An aeroplane takes off by converting fuel into mechanical energy. Without mechanical energy, it will never be able to take off. This guide will help you understand the types of mechanical energy and its importance in the physical systems around us.

MECHANICAL ENERGY DEFINITION

An object’s capacity to perform work is measured using mechanical energy. It is made up of the object’s potential energy and kinetic energy. In simple terms, every human possesses the energy to do work. 

There are two types of energies – energy stored in the human body is potential energy, while the energy acquired due to a state of motion is kinetic. 

Examples of Mechanical energy

• Windmill: It converts wind energy into electricity.

• Fans: The electric motor in a fan converts electrical energy to mechanical energy, which gives the fan blades the ability to rotate.

• Roller coaster: The potential energy builds while going up and gets converted into kinetic energy while coming down.

Importance of mechanical energy

A system that does not exert or intake any form of energy is called a closed system. The capacity of a closed system to provide energy is fixed. Beyond this threshold, the object cannot perform work. And hence mechanical energy is essential for each machine to do work. 

Energy can change into any form, but the amount of mechanical energy cannot change in a system, and it remains constant. 

The potential energy and kinetic energy change alternatively in a closed system, but the mechanical energy remains the same always. This phenomenon is termed the law of conservation. 

TYPES OF MECHANICAL ENERGY

Potential energy and Kinetic energy are the two main types of mechanical energy. In a system, the potential and kinetic energy together are equal to the total mechanical energy of the system. 

Potential energy

An object can develop a certain force when it is put in motion. This force is the potential energy of that object. Potential energy is stored in the body and is expressed when the object starts moving. Physical properties like the object’s mass, position of the object, and height determine the potential energy of the body. 

The formula for potential energy is as follows-

P.E. = mgh 

P.E. → Potential energy

m → mass in kilograms

g → acceleration due to gravity

h → height in metres

Example of potential energy

When we inflate a balloon, the air inside it seems to be stable with no energy. However, the air inside the balloon contains a lot of potential energy that is compressed by the walls of the balloon. As the balloon bursts, it makes a sound that is nothing but a form of energy and further releases kinetic energy into the surrounding.

Different forms of potential energy

1. Elastic potential energy
2. Gravitational potential energy
3. Magnetic potential energy
4. Chemical potential energy
5. Electrical potential energy

Kinetic energy

Kinetic energy is the energy caused due to motion or movement, unlike potential energy. Properties like the speed of the object and the mass influence the kinetic energy of the object. A car that is moving at a faster speed has higher kinetic energy than a car moving at a slower speed. The highest level of the kinetic energy of an object or body is called its highest kinetic energy.

The formula for Kinetic energy is as follows-

K.E. = 1/2 mv2

K.E. → Kinetic energy

m → mass of the object

v → velocity of the object

Example of kinetic energy

Basketball is a perfect example of understanding kinetic energy. When thrown in the air, the ball reaches a certain level and returns to its original position. The highest position that the ball reaches depends on the kinetic energy in the ball. Once the kinetic energy reduces, the gravitational energy acts on the ball to bring it back to the ground. The ball bounces back with the rest of the kinetic energy in the ball and comes to rest when the kinetic energy becomes zero.

Different forms of kinetic energy

1. Radiant energy

2. Thermal energy

3. Sound energy

4. Electrical energy

Conclusion

Mechanical energy is everywhere we look. All movements we perform would be impossible without mechanical energy. The energy storage of an object is its potential energy which is expressed only when the object moves. Once the object moves, it converts its potential energy into kinetic energy that can then convert into numerous types of energy forms. Even breathing is an application of mechanical energy. It is all around us.