## Swimming across a canal

### What is this?

A canal has uniform flow towards the right, with velocity v.
(This flow is made apparent by the piece of "flotsam" depicted on the surface.)
A swimmer is able to swim with constant velocity w, relative to the water.
A ladder is displaced a distance D from the point directly opposite.
Positive D is downstream. The width of the channel is L.
In this physlet, the ladders are fixed at D=-L and D=L.
At what angle γ should the swimmer align his or her body so that
the straight-line trajectory ends exactly at a designated ladder at the opposite shore?
Let γ be measured counterclockwise, with γ=0 to the right.

First consider v/w=1.2.
This means the speed of the water (relative to shore) is faster than the
speed of the swimmer (relative to the water).
Find *two* solutions for γ that allow the swimmer to reach the
downstream ladder.

Next consider v/w=0.8; the swimmer is thus able to swim upstream.
Find the values of γ that allow the swimmer to reach the
upstream and downstream ladder.