What is Elastic potential energy?

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Elastic potential energy in the spring.

Elastic potential energy is the energy which is stored when a body is deformed (as in a coiled spring). The best way to understand elastic potential energy is to study the mechanics of an ordinary spring. Energy, in very simplistic terms, is the capacity to do work. Energy is transferred between two or more objects that are doing work. Usable energy is divided into 2 broad categories - Kinetic energy and Potential energy. Kinetic energy is the energy inherent in a moving objectwhereas Potential energy is the energy stored in an object because of its position or non-equilibrium state. This potential energy is classified into Gravitational potential energy and Elastic potential energy


What is Gravitational potential energy?

Gravitational potential energy is the energy related to the gravitational force. It is the energy stored in an object as result of its vertical position or height. For instance, if we take a heavy ball of demolition, the gravitational energy of the ball is dependent on the mass and height to which the ball is raised. Objects which have more mass also have greater gravitational energy and objects which are elevated higher will have greater gravitational energy. The amount of potential energy an object has, is expressed as P.Egrav = m * g * h, where m is the mass of the object, g is the Earth's gravitational acceleration constant (9.8 m/sec2)  and h is the height of the object


What is Elastic potential energy?

Elastic potential energy is the energy stored in elastic materials when they are stretched or compressed. Elastic potential energy can be stored in springs, bungee chords, an arrow drawn into a bow, rubber bands, etc. The amount of elastic potential energy is more when there is more stretching (directly proportional to stretching). If we take mechanical spring as an example, if there is more force needed to compress a spring then it signifies that there is more compression going on (and hence more energy is being stored in the spring). For some springs the amount of force is directly proportional to the amount of compression (X) and the spring constant (K). That force, can be expressed as Fspring = k * X. We can explain this concept with the help of Hooke’s law


According to the law, there will be no elastic potential energy when there is no stretching or compression of a spring. This is where the spring is considered to be in an equilibrium position. In terms of potential energy, the equilibrium position is known as the zero-potential energy. The equation, which captures the relationship between the amount of elastic potential energy and the amount of stretch, is P. E.spring= ½ *K * X2, where K is the spring constant, X is the amount of stretching or compression (relative to the equilibrium position).


In simple terms we can say that, an object has gravitational potential energy if it is placed at a height above the ground level, and an object is said to have elastic potential energy when if it is in a position that is not its equilibrium position.


What are uses of gravitational and elastic potential energy?

Gravitational potential energy uses:

Elastic potential energy uses:

  • Springs in shock absorbers that are used keep the ride comfortable, while vehicles go over bumps on a road. Those springs convert kinetic energy of the vehicle into elastic potential energy, which is dissipated slowly over the course of the ride, rather than at the instant the vehicle hits a bump
  • Springs in clocks (both hand wound or automatic ones that don't need any winding) that slowly translate elastic potential energy into kinetic energy to move the gears and the hands of the clock
  • Rubber bands or strings in a sling shot or a bow, which translate the elastic potential energy into kinetic energy of the shot or the bow
  • Trampolines that make it fun for everyone to jump without getting hurt - the are a perfect example of how energy is continuously converted between kinetic energy (when you jump down), elastic potential energy (when the trampoline gets stretched), and gravitational potential energy (when the trampoline pushes you up into the air)
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