"1) A river flows due south with a speed of 2.0 m/s . A man steers a motorboat across the river. The river is 800 m wide
a) In which direction should the motorboat head in order to reach a point on the opposite bank directly east from the starting point? (The boat's speed relative to the water is 4.2m/s .)
b) What is the velocity of the boat relative to the earth?
c) How much time is required to cross the river?"