Answer:
The magnitude of the force is 0.7255kN
Explanation:
The elevator floor acts on the person with a force that is due to the gravitational acceleration less the downward acceleration of the elevator:
(force of floor F) = (mass of person m) x [ (grav. acceleration g) - (elevator acceleration a) ]
in other words, considering the elevator floor as a reference frame in the Earth's gravitational field, the person's weight decreases due to the downward acceleration, as follows:
[tex]F = m\cdot(g-a)[/tex]
We are given the person's weight at rest, 0.9kN, from which the mass can be determined as:
[tex]900 N = m\cdot g \implies m = \frac{900N}{9.8 \frac{m}{s^2}}[/tex]
So
[tex]F = \frac{900N}{9.8 \frac{m}{s^2}}\cdot(9.8-1.9)\frac{m}{s^2}\approx 725.5N=0.7255kN[/tex]
