“Energy posses by a body by virtue of its motion is referred to as ‘Kinetic Energy’”.

FORMULA

K.E. = 1/2 mv^{2}

Kinetic energy depends upon the mass and velocity of body.
If velocity is zero than K.E. of body will also be zero.

Kinetic energy is a scalar quantity like other forms of energies.

DERIVE: K.E = 1/2 mv^{2}

PROOF

Consider a body of mass “m” starts moving from rest. After a time interval “t” its velocity becomes V.
If initial velocity of the body is Vi = 0 ,final velocity Vf = V and the displacement of body is “d”. Then

First of all we will find the acceleration of body.

Using equation of motion

2aS = V_{f}^{2} – V_{i}^{2}
Putting the above mentioned values
2ad = V^{2 }– 0
a = V^{2}/2d

Now force is given by
F = ma
Putting the value of accleration
F = m(V^{2}/2d)
As we know that
Work done = Fd

Putting the value of F
Work done = (mv^{2}/2d)(d)
Work done = mV^{2}/2
OR
Work done = ½ mV^{2}

Since the work done is motion is called “Kinetic Energy”
i.e.
K.E. = Work done
OR
K.E. =1/2mV^{2}.