The word kinetic is derived from the Greek word “kinesis” meaning motion. When an object is moving, it possess a energy and such energy is called kinetic energy. The object includes very large things, like planets, and very small ones, like atoms. Heavier objects moves faster and have more kinetic energy. Kinetic energy may be best understood by examples that demonstrate how it is transformed to and from other forms of energy. 
Kinetic Energy Definition

Kinetic energy is one of many types of energy that exist. This is energy generated because something is moving — the faster it's going, the more kinetic energy it has. A person sitting has no kinetic energy, but a person running like a maniac has tremendous kinetic energy:

The energy possessed by a body because of its motion, equal to one half the mass of the body times the square of its speed.

The amount of kinetic energy KE of an object in translational motion is equal to onehalf the product of its mass m and the square of its velocity v.

Kinetic energy is given as follows,
Kinetic energy = ½(mv2) 

Kinetic Energy Formula
 If this force is a net force that accelerates the object (according to Newton’s second law), then the velocity changes due to the acceleration. The change in velocity means that there is a change in the kinetic energy of the object.
 The change in kinetic energy of the object is equal to the work done by the net force acting on it. This is a very important principle called the workenergy theorem. After knowing the relation between work and kinetic energy, how kinetic energy relates to the speed and mass of the object can be found out.


Kinetic Energy Formula
The formula to find kinetic energy, KE, is the following, where m is mass and v is velocity:
Kinetic energy = ½(mv2)
According to newton’s law , force formula is given as
F=ma
Work done is given by the formula as
W=Fscos?
Net force F equals mass times acceleration.
W = Fs = mas


Kinetic Energy Formula (Cont)
Assuming constant acceleration, you can tie this equation to the final and original velocity of the object. Use the formula
Vf2vi2=2as
where vf equals final velocity and vi equals initial velocity.
Solving for a, we get
a= (Vf2vi2) /2s
Now substitute the value of “a” in Net force formula as shown below
W=mas
i.e. W= m*( Vf2vi2) /2s* 2s
i.e. W=1/2(m*( Vf2vi2))


Kinetic Energy Formula (Cont)
If initial velocity is 0, then work done formula is given as
W=1/2*m* Vf2
This is the work to move an ob ject, that is called kinetic energy and the formula is given as,
Kinetic energy = ½(mv2)


Example for kinetic energy calculation
A rocket of mass 1.5x104 kg accelerates at 220m/s2 for 29s from an initial speed of 5200m/s.
(a) How fast will be rocket be travelling after the 29s?
(b) How much Kinetic Energy has the rocket gained?
Solution:
Given:
t = time = 29s
a = acceleration = 220m/s2
v = final speed = ?
u = initial speed = 5200m/s


Kinetic Energy Formula
Formula
(a) a=(vu)/t
v – u = at
v = u + at

KE = ½(mv2)
Calculation:
(a)
v = u + at
v = 5200 + (220 x 29)
= 5200 + 6380
so
v = 11580m/s 

Kinetic Energy Formula
(b)
Now KE=½(mv2)
Initial Kinetic Energy =0.5 x (1.5x104) x (5200)2
=2.028 x 1011J
Final Kinetic Energy =0.5 x (1.5x104) x (11580)2
=1.006 x 1012J
Kinetic Energy gained = Final Kinetic Energy Initial Kinetic Energy
=1.006 x 1012J  2.028 x 1011J
=8.032 x 1011J


Kinetic Energy Formula
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Kinetic Energy Formula
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Kinetic Energy Formula
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Kinetic Energy Formula
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Kinetic Energy Formula
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Kinetic Energy Formula
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