A river with the width of 800 m 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 4.2 m/s due east.
a. How far south of his starting point will he reach the opposite bank?
b. In which direction should the motorboat head in order to reach a point on the opposite bank directly east from the starting point with the same boat speed relative to the water of 4.2 m/s?
c. What is the velocity of the boat relative to the earth?
d. How much time required to cross the river?