A bicyclist makes a trip that consists of three parts, each in the same direction (due north) along a straight road. During the first part, she rides for 18.5 minutes at an average speed of 5.71 m/s. During the second part, she rides for 35.3 minutes at an average speed of 3.38 m/s. Finally, during the third part, she rides for 7.88 minutes at an average speed of 14.5 m/s.