Answer
$49N$
Work Step by Step
The elevator cab is decelerating at $a = -2.4m/s^2$
Spring balance value = $ m a_{net}$
The mass:
$m = \frac{65N}{9.8m/s^2}$
$m =6.63kg$
The net acceleration is calculated by adding the acceleration due to gravity and the deceleration of the cab:
$a_{net} = (g+a)$
Spring balance value = $ 6.63kg$ $ (9.8m/s^2- 2.4m/s^2)$
Spring balance value = $ 49N$
