IIT JEE , AIEEE Forum - Physics , Mechanics

neeraj

Suppose a constant resultant force F acting on a particle of mass m it will produce a constant acceleration a .

Let us choose the x axis to be in the common direction of F and a. Whatever work done by this force will cause a displacement x .

For const. Acc.

a = ( v - v₀ ) / t

x = ( v + v₀ ) / 2 . t

v₀is the particle speed at t = 0

vis the particle speed at t = t

work done w = F . x = m . a . x

= m [ ( v - v₀ ) / t ] . [ ( v + v₀ ) / 2 ]. T

= 1 / 2 m v² - 1/ 2 m v₀²

We call one half the product of the mass of a body and square of its speed the kinetic energy of the body

K = 1 / 2 m v²