Scales- Weight on a scale in an elevator (True/False) Quick

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SUMMARY

The discussion centers on the physics of weight measurement in elevators, specifically analyzing the readings on scales when a person weighing 600 N is in various states of elevator motion. It is established that the mass of the person remains constant regardless of the elevator's movement. The readings on the scale vary based on the elevator's acceleration, with specific scenarios leading to zero normal force. Key conclusions include that the net force on the person is zero in certain conditions, while the scales can read zero weight under specific accelerations.

PREREQUISITES
  • Understanding of Newton's laws of motion
  • Basic knowledge of forces and normal force
  • Familiarity with concepts of weight and mass
  • Knowledge of acceleration and its effects on weight perception
NEXT STEPS
  • Study the effects of acceleration on normal force in physics
  • Learn about free body diagrams and their application in elevator scenarios
  • Explore the relationship between mass, weight, and gravitational force
  • Investigate the principles of inertial frames of reference in physics
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Students studying physics, educators teaching mechanics, and anyone interested in understanding the dynamics of weight measurement in moving systems.

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Homework Statement



The figures depict situations where a person is standing on a scale in eight identical elevators. Each person weighs 600 N when the elevators are stationary. Each elevator now moves (accelerates) according to the specified arrow that is drawn next to it. In all cases where the elevator is moving, it is moving upward.

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Which of the following statements are true about the situations depicted in the figures above?

The mass of the person is different in pictures B and H
The weight the scales read is the same in pictures A, B, C and H
The normal force provided by the scale is zero in pictures G and H
The net force on the person is zero in pictures D, E and G
The scales read zero weight in pictures C, D and F

Homework Equations


The Attempt at a Solution



1. False, mass stays the same. It says each person ways 600N when the elevator is stationary.
2. False, different accelerations read different weights
3. False, wouldn't there be one?
4. True, force on person is zero, force on scale is something else.
5. False, acceleration of gravity is thereWhere am I going wrong?
 
Last edited:
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I'm perhaps not the best person to reply to this, because my knowledge about elevators is very limited. But just using logic:

When you accelerate down in an elevator, don't you feel lighter? For #3 - since you accelerate down with a=g, and gravity is still there, won't they sort of cancel out? So you'll feel weightless and if you feel weightless there shouldn't be a normal force.
 

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