Homework $2$

Problem $5.$ Consider the air over a city to be represented by a box $100$ km on two sides that reaches up to an altitude of $1$ km $.$ Clean air is blowing into the box along one of its sides with a speed of $5\frac{m}{s}($and air is blowing out of the 'box' on the opposite side as well$).$ Suppose an air pollutant with a degradation reaction rate $k=0\mathrm{.}2h^{-1}$ is emitted into the box at a total rate of $10k\frac{g}{s}.$ Find the steady$-$state concentration if the air is assumed to be completely mixed. $(12$ pts $)$