You are in a kayak which can move at a velocity of 3 m/s when in still water. Yo

Question

You are in a kayak which can move at a velocity of 3 m/s when in still water. You are attempting to cross a river which is 111 across and which is flowing to the East at a speed of 0.8 m/s. You head directly North across the river. Part A How long does it take you to get to the other side? t = Part B How far downriver are you when you reach the other side of the river? D = Part C If you now head back upriver, how long does it take you to reach a point on the river opposite from where you started?

Explanation / Answer

When the student swims upstream, the speed of the current subtracts from the student's normal swimming speed. So the student's speed (relative to the riverbank) is: speed_upstream = (swim_speed) - (river_speed) = Use the usual formula (time = distance/speed) to figure the time it takes to go upstream: time_upstream = distance / speed_upstream When the student swims downstream, the speed of the current ADDS to the student's swimming speed: speed_downstream = (swim_speed) + (river_speed) = So the time for the downstream trip is: time_downstream = distance / speed_downstream Finally, just add time_upstream + time_downstream to get the total time. > How much longer or shorter will the trip be if the river is standing still? Hah! A "river standing still" is an odd concept. But anyway: no current, so the student's speed is just the same as their swimming speed: time_there = distance / swimming_speed time_back = distanct / swimming_speed total_time = time_there + time_back

Related Questions

Navigate

• Browse (All)
• Browse Y
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.