Question
And there is no picture to go with this problem, so what point is marked x?
A swimmer crosses a stream which has a flow of 2 m/sec. The swimmer swims at 4 m/sec. with respect to the water. Knowing that he will be washed downstream, he aims upstream to compensate but he has never had a physics class and doesn't know how to find the correct angle. He guesses at an angle of 20 degrees from the straight across direction as shown. If the river is 40 meters wide, how far from the point marked X does he reach as he crosses?
Explanation / Answer
time taken=40/(4*cos(20))=10.64 sec so distance=(2-4*sin(20))*10.64=6.724 m