Weight of a person in a elevator going down

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    Elevator Weight
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Homework Help Overview

The discussion revolves around the physics of a person standing on a scale in an elevator that is descending with constant acceleration. The subject area includes concepts of forces, acceleration, and apparent weight in the context of classical mechanics.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • Participants are attempting to calculate the reading on a scale based on different scenarios of elevator acceleration. Questions are raised regarding the implications of constant acceleration on the effective weight of the passenger and how the normal force relates to the scale reading.

Discussion Status

Some participants have provided calculations and reasoning regarding the forces acting on the passenger. There is an exploration of how the normal force changes with the elevator's motion, and multiple interpretations of the apparent weight are being discussed.

Contextual Notes

Participants are working within the constraints of a homework problem, focusing on the effects of acceleration on weight readings without resolving the calculations completely.

stealthcataf
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Im new to physics and I am trying to do some problems here, I hope someone can help me, here it goes :

If a passenger with a mass of 72.2kg stands on a weight scale in a elevator. What is the reading on the scale if the elevator goes down with a constant acceleration of 3.20 m/s^2.
 
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If the elevator was descending at constant acceleration of 9.8m/s^2, what would the scale read? Why?

What does this tell you about the effective acceleration on the passenger?
 
Ive done some calcs, correct me if I am wrong

m=72.2kg
a=-3.20 m/s^2

SumFx=0
SumFy=Fn-mg=ma

ma=72.2(-3.20)=-231.04n

Fn=mg+ma=72.2(-9.8)+72.2(-3.20)=-938.6n
Is this the apparent weight?
 
If the elevator is going down, then is he pressing MORE on the scale or less?
It is the normal force that gives the reading on the scale. How is the normal force affected when the elevator is falling?
 
Weight of person=72.2*9.81=708.282
upward lift on person=72.2*3.2=231.04
Therefore net 'weight' of person=708.282-231.04=477.242
 

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