$(9$ Pts$)$ For a rectangular experimental flume that has a channel width of $3$ inches a flow of $1\mathrm{.}5$ liters $\frac{?}{sec},$ and a normal depth of $7cm.$ Answer the following questions:

a$.$ What is the critical depth?

b$.$ Is the flow classified as critical, subcritical, or supercritical?

c$.$ If a hump of $0\mathrm{.}635cm$ is placed across the bottom of the channel, calculate the water depth on the hump.