MCQ
A force applied by an engine of a train of mass $2.05 \times {10^6}\;kg$ changes its velocity from $5\;m/s$ to $25\;m/s$ in $5$ minutes. The power of the engine is ........... $MW$
- A$1.025$
- ✓$2.05$
- C$5$
- D$6$
✓
Answer
Correct option: B.
$2.05$
b
(b)Power$ = \frac{{{\rm{Work done}}}}{{{\rm{time}}}} = \frac{{\frac{1}{2}m({v^2} - {u^2})}}{t}$
P$ = \frac{1}{2} \times \frac{{2.05 \times {{10}^6} \times [{{(25)}^2} - ({5^2})]}}{{5 \times 60}}$
$P = 2.05 \times {10^6}\,W = 2.05\,MW$
(b)Power$ = \frac{{{\rm{Work done}}}}{{{\rm{time}}}} = \frac{{\frac{1}{2}m({v^2} - {u^2})}}{t}$
P$ = \frac{1}{2} \times \frac{{2.05 \times {{10}^6} \times [{{(25)}^2} - ({5^2})]}}{{5 \times 60}}$
$P = 2.05 \times {10^6}\,W = 2.05\,MW$
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