Question

Water current in a river from east to west has the speed of $4m/s$. A boat starts moving at $10m/s$ from south bank to reach the north bank. If boat started at ${30}^o$ with current, then determine the drift of boat while crossing $40m$ wide river is nearly

• A. $4+5\sqrt{3}m$
• B. $20m$
• C. $100m$
• D. $50m$

Answer 1

Answer: (A)

$4+5\sqrt{3}m$

$V_{\omega }=4m/s$

$V_{s\omega }=10m/s$

$t=\frac{\omega }{V_{s\omega }\sin 30}=\frac{40}{810\times \frac{1}{2}}$

$\Delta x=(V_{\omega }+V_{s\omega }\cos 30)$

$=(4+5\sqrt{3}$)