Answer
$$h =\left(-16 t^{2}+750 t\right) \mathrm{ft}$$
Work Step by Step
Given $v= 1500$ ft/sec , $ \theta =30 $ and
$$ h=-16t^2+vt\sin \theta $$
Then
\begin{aligned}
h &=\left(-16 t^{2}+1500 \times \sin 30^{\circ} \times t\right) \\ &=\left(-16 t^{2}+1500 \times \frac{1}{2} \times t\right) \\
&=\left(-16 t^{2}+750 t\right) \mathrm{ft}
\end{aligned}
