Question

A force applied by an engine of a train of mass $2.05\times 10^{6}kg$ changes its velocity from $5ms^{- 1}$ to $25ms^{- 1}$ in $5$ minutes. The power of the engine is :-

• A. $1.025MW$
• B. $2.05MW$
• C. $5MW$
• D. $6MW$

Answer 1

Answer: (B)

Power $=\frac{Work done }{ time }=\frac{\frac{1}{2} m \left(v^{2} - u^{2}\right)}{t}$
$=\frac{1}{2}\times \frac{2 . 05 \times \left(10\right)^{6} \times \left(\left(25\right)^{2} - 5^{2}\right)}{5 \times 60}$
$P=2.05\times 10^{6}Watt=2.05MW$