Physics - W.E.P. Question with Solution | TestHub

Power of engine,

$P=58.8 \mathrm{kW}=58.8\times {10}^3\mathrm{ W}$

Mass of the train,$m=2\times {10}^5\mathrm{ kg}$

Velocity of train,$v=36 \mathrm{km}{\mathrm{h}}^{-1}$

$=\frac{36\times {10}^3}{60\times 60}=10\mathrm{ m }{\mathrm{s}}^{-1}$

Power,$P=F\cdot v$

$\therefore F=\frac{P}{v}=\frac{58.8\times {10}^3}{10}$

$=5880 \mathrm{N}$

Let the coefficient of friction is$\mu$

$\therefore F=f_s=\mu mg$

$\Rightarrow \mu =\frac{F}{mg}=\frac{5880}{2\times {10}^5\times 10}$

$=0.003$