$5\mathrm{.}45$ The air$-$conditioning system in a Chevrolet van for use in desert climates is to be sized. The system is to maintain an interior temperature of $20C$ when the van travels at $100k\frac{m}{h}$ through dry air at $30C$ at night. If the top of the van is idealized as a flat plate $6$ m long and $2$ m wide and the sides as flat plates $3$ m tall and $6$ m long, estimate the rate at which heat must be removed from the interior to maintain the specified