Suppose water flows through a square surface of area A with a
uniform velocity
.
We want to define flux as the amount of water that flows through
the surface per second. First, notice that the flux depends on the
direction of the velocity vector relative to the surface.
Compare the water flux in the following three situations. Rank the
flux in cases (a), (b), and
(c), from largest to smallest.
(a)
(b)
(c)
Once you're ready, move on to the next section to learn more about flux.