MCQ
A man is crossing a river flowing with velocity of $5\,\, m/s$. He reaches a point directly across at a distance of $60\,\, m$ in $5 \,\,sec$. His velocity in still water should be ........ $m/s$
- A$12$
- ✓$13$
- C$5$
- D$10$
✓
Answer
Correct option: B.
$13$
b
$t=\frac{d}{\sqrt{v^{2}-u^{2}}}$
$t=\frac{d}{\sqrt{v^{2}-u^{2}}}$
$\Rightarrow 5=\frac{60}{\sqrt{v^{2}-5^{2}}} \Rightarrow v=13 \mathrm{m} / \mathrm{s}$
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