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

# A man can swim at the rate of 5kmh−1 in still water. A 1-km wide river flows at the rate of 3kmh−1. The man wishes to swim across the river directly opposite to the starting pointa. Along what direction must the man swim?b. What should be his resultant velocity?c. How much time will he take to cross the river?

Open in App
Solution

## a. Velocity of man with respect to river water, v=5kmh−1. This is greater than the river flow velocity. Therefore, he can cross the river directly (along the shortest path or no drift condition from flow velocity). The angle of swim,θ=π2+sin−1(uv)=90o+sin−1(uv)=90o+sin−1(35)=90o+37o=127o w.r.t. the river flow or 37o w.r.t. the perpendicular in upstream directionb. Resultant velocity or velocity of mass will bevm=√v2−u2=√52−32=4kmh−1In the direction perpendicular to the river flow.c. time taken to cross the rivert=d√v2−u2=1km4kmh−1=14h=15min

Suggest Corrections
0
Join BYJU'S Learning Program
Related Videos
Motion Under Constant Acceleration
PHYSICS
Watch in App
Explore more
Join BYJU'S Learning Program