A river is flowing 4.0 m/s to the east. A boater on the south shore plans to reach a dock on the north shore 30.0 Degrees downriver by heading directly across the river. What should be the boat's speed relative to the water?

Answer 1

you know the angle, so sin30=4/V
solve for V

Answer 2

a boat sails steadily across a river ,with velocity 20 m/s. if the river has width 30 m, how long does it take the boat to get across ,and how far downstream is it swept by the currenty first