$1.)$ Problem $11\mathrm{.}6$ from the textbook.

Consider the performance of a solid$-$propellant rocket under conditions which change

with time. The stagnation temperature is constant at $5000R.$ The stagnation pressure

changes slowly with time, according to

$p_{0}t1f{t}^2=\frac{1\mathrm{.}4}{b}ar(M)=20p_0=1000-3t,0$

for $p_{0}in$ psia and $tin$ seconds. The nozzle has $an$ area ratio $of5$ and a throat area $of$

$1f{t}^2.It$ exhausts into a vacuum. The fiuid may $be$ considered $to$ have $=1\mathrm{.}4$ and

molecular weight $\frac{?}{\text{b}\text{a}\text{r}}(M)=20.$ How $do$ the following vary with time? $(1)$ Exhaust velocity.

$(2)$ Mass flow. $(3)$ Thrust.