Question

A river $400m$ wide is flowing at a rate of $2.0m/s$. A boat is sailing at a velocity of $10.0m/s$ with respect to the water, in a direction perpendicular to the river. Find the time taken by the boat to reach the opposite bank.

• A. $20s$
• B. $20\sqrt{2}s$
• C. $40s$
• D. $40\sqrt{2}s$

Answer 1

The correct option is C $40s$


Here $\theta$ is zero
As it is given that boat is sailing in a direction normal to current.
Crossing velocity of boat is $=10m/s$
So time taken by the boat to reach the other bank is $=\frac{s}{v}=\frac{400}{10}=40s$