A lunar lander is descending toward the moon's surface. Until thWhat is the velocity of the lander just before it reaches the lunar surface?e lander reaches What is the initial velocity of the lander, at t

$=0?$the surface, its height above the surface of the moon is given by y$($t$)=$b$$ct$+$dt$2$

$,$ where b

$=800$ m

is the initial height of the lander above the surface, c

$=63\mathrm{.}0$ m$/$s

$,$ and d

$=1\mathrm{.}01$ m$/$s$2$

$.$