Physics Study Guide/Kinetic energy

Kinetic energy The energy possessed by a body due to its motion is called kinetic energy. Energy of running water moving wind, moving vehicles, moving fan, etc are some examples of kinetic energy. Kinetic energy depends upon the velocity and the mass of moving body. The kinetic energy of a body can be calculated by following formula: Kinetic energy(K.E.)=1/2(m*v^2) (Where m is mass and v is velocity)

Derivation of the formula of kinetic energy :

Let us consider a body of mass`m´ initially at rest(I.e.,u=0)reaches a final velocity`v´ while attaining the acceleration`a´. Let`s´ be the distance covered:

We have ,v^2=u^2+2*a*s
               or,v^2=0^2+2*a*s
               or,a*s=v^2/2.....................(1)
Now, the work done by the  force:W=F*S and F=m*a

Hence,W=m*a*s................(2) From equation (1) and (2), we get, W=1/2(m*v^2) Therefore, kinetic energy = 1/2(m*v^2).