Jon is attempting to swim straight across a swift flowing river that is 30 meters wide. Jon can swim at 5 m/s relative to the water. The current is moving at 7 m/s and Jon makes no correction for the current. How far downstream does Jon end up by the time he reaches the other shore?
how much time does it take to swim across?
time=distancewide/speed
How far downstream? distance=currentspeed*time
To determine how far downstream Jon ends up, we need to find the time it takes him to cross the river and then multiply that by the velocity of the current.
The time it takes for Jon to cross the river can be found by dividing the width of the river by his swimming speed relative to the water:
Time = Distance / Speed
Time = 30 meters / 5 m/s
Time = 6 seconds
Now that we know it takes Jon 6 seconds to cross the river, we can find how far downstream he ends up by multiplying the time by the velocity of the current:
Distance downstream = Time * Current velocity
Distance downstream = 6 seconds * 7 m/s
Distance downstream = 42 meters
Therefore, Jon ends up 42 meters downstream by the time he reaches the other shore.