A brass ball is shot vertically upward from the surface of an atmosphere$-$free planet with an initial speed of $20\mathrm{.}0$ m$/$s$.$ One second later,

What is the magnitude of the acceleration due to gravity on the surface of this planet?

$998$m$/2$

O $24$ m$/$s$<$

$5\mathrm{.}0$ m$/$s$<$

$15$ m$/$s$-$

$012$m$/$s$?$