Answer:
a = - 1.47 [m/s²], descending or going down
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 = 10 [kg]
a = acceleration [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 measured by the scale = 83.4 [N]
Now replacing:
The acceleration has a negative sign, this means that the elevator is descending at that very moment.