A boat needs to travel straight across a river. The current is 10 km/hr. The boat can travel at 16 km/hr. What is the velocity of the boat relative to the bank?

Answer 1

If the boat is headed upstream, so that it moves directly across the stream, then
sinTheta=10/16 where theta is the angle upstream frm the line across.

then velocity across= 16cosTheta

Answer 2

a boat can travel 3m/s in still water. a boatman wants to cross a river while covering shortest distance. how long will it take him to cross the river if speed of water is (a) 2m/s (b) 4 m/s