A boat is sent across a river with a velocity of 8 km per hour. if the resultant velocity of boat is 10 km per hour then calculate the velocity of the river.
A river flows due south with a speed of 2.0 m/s. A man steers a motorboat across the river; his velocity relative to the water is 4 m/s due east. The river is 800 m wide. What is his velocity relative to the earth? Assume North as positive y-direction.