Quiz – Finding the Time Needed to Cross a River Physics 12Quizzes based on the BC Physics 12 curriculum. Finding the Time Needed to Cross a River 1 / 1 A hiker travelling West comes to a river that flows North. The hiker wants to swim straight West across the river. If they can swim at a rate of 0.90 m/s and the river has a speed of 0.70 m/s and a width of 87 m, how long will it take them to cross the river? Answer in the form '28 s'. Check Quiz(PDF) Questions(PDF) Your score is 0% Try new quiz By Wordpress Quiz plugin