Answer
4.11 m/s.
Work Step by Step
The lander has a constant downward acceleration. We know the initial velocity of -0.8 m/s and the displacement of -5.0 m. Use the kinematics formulas for constant acceleration.
$v_f^2=v_o^2+2a(\Delta x)$
$v_f^2=(-0.8m/s)^2+2(-1.6m/s^2)(-5.0m)$
$v_f=4.1 m/s$
