1
You visited us 1 times! Enjoying our articles? Unlock Full Access!
Question

# A man wants to reach point B on the opposite bank of a river flowing at a speed as shown in figure. What minimum speed relative to water should the man have so that he can reach point B? In which direction should he swim ?

A

2u

No worries! Weâ€˜ve got your back. Try BYJUâ€˜S free classes today!
B

u/2

No worries! Weâ€˜ve got your back. Try BYJUâ€˜S free classes today!
C

$\frac{u}{\sqrt2}$

Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
D

$\frac{3u}{\sqrt2}$

No worries! Weâ€˜ve got your back. Try BYJUâ€˜S free classes today!
Open in App
Solution

## The correct option is C $\frac{u}{\sqrt2}$ Let v be the speed of boatman in still water. Resultant of v and u should be along AB. Component of â†’vb (absolute velocity of xboatman) along x and y- direction are, vx=uâˆ’vsin Î¸ and vy=v cos Î¸Further, tan450=vyvx1=v cos Î¸uâˆ’v sin Î¸âˆ´ v=usin Î¸+cos Î¸=uâˆš2sin(Î¸+450)v is minimum at,Î¸+450=900 or Î¸=450and vmin=uâˆš2

Suggest Corrections
0
Join BYJU'S Learning Program
Related Videos
Relative
PHYSICS
Watch in App
Join BYJU'S Learning Program