## College Physics (4th Edition)

We can rank the scale readings from highest to lowest: $a \gt b = c \gt d = e$
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: $a \gt b = c \gt d = e$