Answer:
N = 648.55[N]
Explanation:
To solve this problem we must use Newton's second law which tells us that the sum of forces on a body is equal to the product of mass by acceleration.
∑F = m*a
where:
∑F = Forces applied [N]
m = mass = 73.2 [kg]
a = acceleration = 0.950 [m/s²]
Let's assume the direction of the upward forces as positive, just as if the movement of the box is upward the acceleration will be positive.
By performing a summation of forces on the vertical axis we obtain all the required forces and other magnitudes to be determined.

where:
g = gravity acceleration = 9.81 [m/s²]
N = normal force (or weight) measured by the scale = 83.4 [N]
Now replacing:
![-(73.2*9.81)+N=-73.2*0.950\\-718.092+N=-69.54\\N = -69.54+718.092\\N = 648.55[N]](https://tex.z-dn.net/?f=-%2873.2%2A9.81%29%2BN%3D-73.2%2A0.950%5C%5C-718.092%2BN%3D-69.54%5C%5CN%20%3D%20-69.54%2B718.092%5C%5CN%20%3D%20648.55%5BN%5D)
The acceleration has a negative sign, this means that the elevator is descending at that very moment.