Magnitude of the Acceleration of an Elevator when it first begins to move

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SUMMARY

The discussion focuses on calculating the magnitude of the acceleration of an elevator when it first begins to move, based on the reading of a bathroom scale. The scale reads 0.88 times the person's weight, indicating a net force acting on the person. The correct formula for acceleration is derived as a = (F_n - F_g)/m, where F_n is the normal force (scale reading) and F_g is the gravitational force (weight). The user initially miscalculated the acceleration, leading to confusion about the result.

PREREQUISITES
  • Understanding of Newton's Second Law (F=ma)
  • Knowledge of gravitational force calculation (w=mg)
  • Basic algebra skills for solving equations
  • Familiarity with the concept of normal force in physics
NEXT STEPS
  • Study the derivation of Newton's Second Law in various contexts
  • Learn about the concept of normal force and its applications
  • Practice solving problems involving forces in motion, particularly in elevators
  • Explore the effects of acceleration on weight readings in different scenarios
USEFUL FOR

Students studying physics, particularly those focusing on mechanics and forces, as well as educators looking for examples of real-world applications of Newton's laws.

xsorealx
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Homework Statement



A person stands on a bathroom scale in a motionless elevator. When the elevator begins to move, the scale briefly reads only 0.88 of the person's regular weight.

Calculate the magnitude of the acceleration of the elevator.


Homework Equations



w=mg
F=Ma

The Attempt at a Solution



Fn-Fg=ma
A=Fn-Fg/m
A=9.8-9.8/.88

I know that answer is definitely wrong because it can't be 0.

I am completely stuck on this problem, any help would be appreciated, thanks!
 
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xsorealx said:

Homework Statement



A person stands on a bathroom scale in a motionless elevator. When the elevator begins to move, the scale briefly reads only 0.88 of the person's regular weight.

Calculate the magnitude of the acceleration of the elevator.


Homework Equations



w=mg
F=Ma

The Attempt at a Solution



Fn-Fg=ma
A=Fn-Fg/m
A=9.8-9.8/.88

I know that answer is definitely wrong because it can't be 0.

I am completely stuck on this problem, any help would be appreciated, thanks!
xsorealx, welcome to PF!
Your algebra is off, and so is your calculation for the variables. It's a = (F_n - F_g)/m, where F_g = mg, and F_n is the scale reading.
 

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