Answer
$y_{0}=897$ m
Work Step by Step
We have$:$
$v_{0}=80.6$ m/s$,\quad t=10.0$ s, $\quad \theta_{0}=-30.0^{o}, $final height =$y=0.$
Solve Eq. 4-22 to solve for the initial height $y_{0}$:
$y-y_{0}=(v_{0}\displaystyle \sin\theta_{0})t-\frac{1}{2}gt^{2}$
$0-y_{0}=(-40.3\displaystyle \mathrm{m}/\mathrm{s})(10.0\mathrm{s})-\frac{1}{2}(9.80\mathrm{m}/\mathrm{s}^{2})(10.0\mathrm{s})^{2}$
$-y_{0}=-897$ m
$y_{0}=897$ m
