Answer
We can rank the scale readings from highest to lowest:
$a \gt b = c \gt d = e$
Work Step by Step
Let $F_N$ be the normal force of the scale pushing up on the person in the elevator. Note that $F_N$ will be the reading on the scale. Let $M$ be the person's mass.
(a) $\sum F = Ma$
$F_N -Mg = Ma$
$F_N = M~(g+a)$
$F_N = M~(10.8~m/s^2)$
(b) $\sum F = Ma$
$F_N -Mg = 0$
$F_N = Mg$
$F_N = M~(9.8~m/s^2)$
(c) $\sum F = Ma$
$F_N -Mg = 0$
$F_N = Mg$
$F_N = M~(9.8~m/s^2)$
(d) $\sum F = Ma$
$Mg-F_N = Ma$
$F_N = M~(g-a)$
$F_N = M~(7.8~m/s^2)$
(e) $\sum F = Ma$
$Mg-F_N = Ma$
$F_N = M~(g-a)$
$F_N = M~(7.8~m/s^2)$
We can rank the scale readings from highest to lowest:
$a \gt b = c \gt d = e$
