Q. If F is the force required to keep a train moving at a constant speed $v,$the power required is
A) $\frac{1}{2}Fv^{2}$
B) $Fv^{2}$
C) $\frac{1}{2}Fv\ $
D) $Fv$
Explanation
(d) The rate of doing work by a train is called power.
Power=$\frac{work}{time}$
And work=force(F)$\times$displacement(s)
Power=$F \times \frac{F \times s}{t}$
Or $P = F \times \frac{s}{t}$
Or $\ \ \ \ \ P = F \times v$ $\left\lbrack \therefore v = \frac{s}{t} \right\rbrack$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.