Q. A particle of mass $m$ at rest is acted upon by a force $F$ for a time $t$. Its kinetic energy after an interval $t$ is
A) $\frac{F^{2}t^{2}}{m}$
B) $\frac{F^{2}t^{2}}{2m}$
C) $\frac{F^{2}t^{2}}{3m}$
D) $\frac{Ft}{2m}$
Explanation
(b) Kinetic energy $E = \frac{P^{2}}{2m} = \frac{(Ft)^{2}}{2m} = \frac{F^{2}t^{2}}{2m}$ [As $P = Ft\rbrack$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.