- #1

hueyosie

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## Homework Statement

An object is hung from a spring scale attached to the ceiling of an elevator. The scale reads 65 N when the elevator is standing still. What is the reading of the scale when the elevator is moving upward with a speed of 7.6 m/s and decelerating at 2.4 m/s^2?

## Homework Equations

F=ma

## The Attempt at a Solution

I know that I should use the F=ma equation but according to the solutions guide, I should use F=ma=Wa/g to get (65 N)(-2.4 m/s^2)/(9.81 m/s^2) = -16 N

then do -16N-(-65N) = 49N. I am not understanding where the Wa/g part came from or why I should subtract -65N from -16N. Any help would be much appreciated! I'm having a lot of trouble with my physics class :(