Answer
A
Work Step by Step
Let the positive direction be upward with origin on the lunar surface.
$1~ft=0.305~m$
$4.30~ft=(4.30~ft)(\frac{0.305~m}{1~ft})=1.3115~m$
$0.500~ft/s=(0.500~ft/s)(\frac{0.305~m}{1~ft})=0.1525~m/s$
$v_0=-0.1525~m/s$, $a=-g_{moon}=-1.62~m/s^2$, $x_0=1.3115~m$, $x=0$
$x=x_0+v_0t+\frac{1}{2}at^2$
$0=1.3115~m+(-0.1525~m/s)t+\frac{1}{2}(-1.62~m/s^2)t^2$
$(0.81~m/s^2)t^2+(0.1525~m/s)t-1.3115~m=0$
$t=\frac{-(0.1525~m/s)±\sqrt {(0.1525~m/s)^2-4(0.81~m/s^2)(-1.3115~m)}}{2(0.81~m/s^2)}$
$t_1=1.18~s$
$t_2=-1.37~s$ (this solution is not valid)
