2. A boat is used to cross a river 5.0 km wide, which is flowing at 15.0 km/h [E]. In still water, the boat travels with a constant speed of 25.0 km/h. In the following questions, all angles are measured counter clockwise from the direction of flow of the river. a. At what angle should the boat be pointing (its \"heading\") in order to travel to a point on the opposite bank ofthe river, directlv across from its starting point? Draw a clearly labeled diagram including all relevant vectors, angles, and distances. (? marks) b. How many minutes does the boat in part a. take to reach the other side? (2 marks) c. If the boat travels (its \"course") at an angle 135\" counter clockwise from the direction of the flow of the river, what is the boat's velocity relative to the Earth? Draw a clearly labeled diagram including all relevant vectors and angles. (10 marks) d. At what angle should the boat be pointing (its \"heading") so that the time taken to cross the river is a minimum? Sketch all relevant velocitv vectors in this situation. [1 mark)