When a net force does work on an object, its kinetic energy changes.

$W_{\text{n}\text{e}\text{t}}=\frac{1}{2}m(v_f^2-v_i^2)=K.$

$($g$)$ A particle of charge $|q_e|=2^{**}{10}^{-6}C$ and mass $m=3^{**}{10}^{-8}kg$ is released from rest at point W $.$ The speed of the particle is measured to be $25\frac{m}{s}$ as it passes point X $.$