Calculate Elevator Accel. - FN=mg+ma

  • Thread starter Thread starter mpd105
  • Start date Start date
  • Tags Tags
    Elevator
Click For Summary
SUMMARY

The discussion focuses on calculating the acceleration of an elevator based on the reading of a bathroom scale. When the elevator begins to move, the scale reads 0.71 times the person's weight, indicating a downward acceleration. The relevant equation used is FN = mg - ma, where FN is the normal force, m is mass, g is gravitational acceleration, and a is the acceleration of the elevator. The solution involves rearranging the equation to find the acceleration based on the scale's reading.

PREREQUISITES
  • Understanding of Newton's Second Law of Motion
  • Familiarity with the concepts of normal force and gravitational force
  • Basic algebra for rearranging equations
  • Knowledge of the relationship between weight and mass
NEXT STEPS
  • Study the implications of varying normal force in different acceleration scenarios
  • Learn about free body diagrams to visualize forces acting on objects
  • Explore the effects of upward and downward acceleration on scale readings
  • Investigate real-world applications of elevator physics in engineering
USEFUL FOR

This discussion is beneficial for physics students, educators, and anyone interested in understanding the dynamics of forces in motion, particularly in relation to elevators and similar systems.

mpd105
Messages
1
Reaction score
0

Homework Statement


A person stands on a bathroom scale in a motionless elevator. When the elevator begins to move, the scale briefly reads only 0.71 of the person's regular weight. Calculate the magnitude of the acceleration of the elevator.


Homework Equations


FN=mg+ma


The Attempt at a Solution


With the way the problem is worded, I'm assuming that the elevator is going down, which could mean that the equation should be FN=mg-ma? Other than assuming that I really have no idea how to start this problem.
 
Physics news on Phys.org
You are in an elevator at rest standing on a scale. What are the forces that act on you?

Sum F = N - mg = o

Now the elevator accelerates downward with acceleration a, what are the forces that act on you?

Sum F = N' - mg = ma

But N' = .71mg
 

Similar threads

  • · Replies 9 ·
Replies
9
Views
4K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 10 ·
Replies
10
Views
4K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 9 ·
Replies
9
Views
5K
  • · Replies 5 ·
Replies
5
Views
3K
  • · Replies 6 ·
Replies
6
Views
4K
  • · Replies 1 ·
Replies
1
Views
3K
  • · Replies 4 ·
Replies
4
Views
2K
Replies
5
Views
2K