#### • Class 11 Physics Demo

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# Difference between Force and Energy

Energy is one of the fundamental characteristics of any and every object. Every object possesses some energy in one form or other. It is a well-known fact that Energy cannot be created nor can be destroyed but can only change form. A stationary object has a potential energy while a moving object has a kinetic energy. The energy can be defined, in terms of equation, as;

E = m c2;

M – mass of object;

C = Velocity of light.

The energy is measured in Joule (Newton – meter) in S.I. units. The energy can also be defined as work done by one object on another object to move it for one unit distance with a force of 1 Newton. Therefore the unit of energy is Newton – meter or Joule. This unit is also the unit of work and heat dissipated by an object.

Although the work and energy have common units however the energy is necessary for accomplishing the work on the object. If the object does not possess any energy then the work cannot be done on the object.

Force is a pressure exerted or work done by an external entity to make an object change its state. For example a stationary object may change its position from stationary to moving when an external force is applied to it. In this case the stationary object which possesses potential energy has its energy converted to the kinetic energy by the application of the external force.

The force can be defined, in terms of equation, as;

F = m * a;

M = mass of object;

A = Acceleration of the object.

The force is measured in Newton in S.I. units.

The force and energy are interrelated, since from the above discussion it is cleared that the energy changes its form after an external force is applied to it. The famous energy equation e = mc2, is only possible if the relation between the force and the energy exists as discussed previously otherwise the equation has no relevance to study.

In simple words we can say that some force need to be applied to change the energy state of the object. The force disturbs the equilibrium and hence the transformation of energy from one form to another.

From the units of both the force and energy it is clear that the energy is the force per unit of length, which means that the energy is equal to force for a unit meter.

Example of force:

If a body of mass 15 kg is accelerating with 20 meter per second square, find the force experienced by the body?

We know that the force is the product of the mass and acceleration and hence the force on the body would be;

F = 15 * 20 = 300 Newton.