- #1

racecar12

- 19

- 1

## Homework Statement

Person weighing 0.9kN rides in an elevator that has downward acceleration of 1m/s^2. What is the magnitude of the force of the elevator floor on the person. Answer in units of kN.

## Homework Equations

F=ma

## The Attempt at a Solution

I drew a force body diagram and set y upward to be the positive y direction. The relevant forces acting on the person are then 1) -1m/s^2 and 2) -9.8m/s^2 due to gravity and 3) the normal force of the elevator floor that pushes up in the positive y direction. That's the one I am solving for.

Sum of the forces in the y direction have to equal each other, right?

I have three forces working in the y direction.

So F becomes N, the normal force of the elevator yielding: N=ma.

I'm guessing a then is just the sum of the two accelerations? So, -9.8 + -1 =-10.8

Then N = 0.9kN(-10.8)...N=-9.72kN?