Kinetic Energy Formula

Before written down the Kinetic Energy Formula, we know firstly, what is Energy? And What is Kinetic Energy? And then we get the formula after considering an example.

An Energy is the ability to do the work. The energy is stored in a body and when the work is done on it, the body performs a work due to its energy.

Energy is found in many forms like Nuclear, Electrical, Magnetic, Chemical, Mechanical and so on.

Now we are in a position to define Kinetic Energy:

Kinetic Energy Definition

“Kinetic Energy is stored by a body due to its Motion”

Kinetic Energy Example

Let suppose, a body having mass m is moving with an initial velocity V_i,  and a constant force F is applied on the body to stop it, then according to Newton’s Second Law of Motion, the acceleration is given as:

a = - F / m

As body comes to rest after converting some distance d, its velocity V_f is zero, and according to Second Motion of Equation or Kinematic Equations, we get:

2ad = Vf² - Vi² =  2 (- F / m ) d = Vf² - Vi²

-2Fd / m = 0² – Vi²

2Fd = mvi²

Fd = mvi² / 2    ----- (i)

Here Fd should be the work done due to energy stored in the body due to the motion before the body will come to a rest position against the opposite force that tries to stop the body. This opposite force must be equal to the energy possessed by the body due to the motion, so can write the above Equation (i) as:

Kinetic Energy (K.E.) = 1/2 mv²

Or

K.E. = 1/2 m (v.v)

Kinetic Energy is a scalar quantity and its unit is Joule similar to Work’s Unit.