A swimmer can swim at a speed of 0.7 m/s with respect to the water. She wants to cross a river which is 50m North and has a current of 0.5 m/s East. (a) If she wishes to land on the other bank directly at a point directly across from her starting point, in what direction must she swim? How long will it take? (b) 1,5g instead decides to cross in the shortest possible time, in what direction must she swim? How far down stream will she be?