According to this theorem, "Work done by a force in displacing an object on horizontal surface, is equal to increase in its kinetic energy." i.e.,
W = Kf - Ki
Proof: (i) When force is constant.
According to third equation of motion,
\(v^2 = u^2 + 2\vec a\vec s\)
or \(v^2 - u^2 =2\vec a\vec s\)
Multiplying the whole equation by \(\frac{m}{2}\), we have,
(ii) When force is variable.
∵ Kinetic energy,
K = \(\frac{1}{2}\)mv2
∴ Rate of change of kinetic energy
or dK = F dx
On integrating both sides,
