Q123 / 160 · TS EAMCET 2017 · Physics
A swimmer wants to cross a $200 \mathrm{~m}$ wide river which is flowing at a speed of $2 \mathrm{~m} / \mathrm{s}$. The velocity of the swimmer with respect to the river is $1 \mathrm{~m} / \mathrm{s}$. How far from the point directly opposite to the starting point does the swimmer reach the opposite bank?
- A$200 \mathrm{~m}$
- Correct answerB$400 \mathrm{~m}$
- C$600 \mathrm{~m}$
- D$800 \mathrm{~m}$
Solution
Given,
Width of river $(w)=200 \mathrm{~m}$
Velocity of river $=2 \mathrm{~m} / \mathrm{s}$
Velocity of mans $=1 \mathrm{~m} / \mathrm{s}$
We krow that,
$$
\begin{aligned}
\frac{W}{V_{\mathrm{man}}} & =\frac{d}{V_{\text {strem }}} \\
d & =\frac{W \times v_{\text {strem }}}{V} \\
d & =\frac{200 \times 2}{1} \\
d & =400 \mathrm{~m}
\end{aligned}
$$
Hence, the correct answer is option: 'B'.