Conceptual question concerning forces and scales and elevators

In summary, the conversation discusses the concept of a man in an elevator standing on a bathroom scale. The scale reads different numbers depending on whether the elevator is going up or down, leading to the question of what the scale is measuring. The conversation also touches on Newton's first law and the concept of normal force, with the conclusion that the scale measures normal force rather than weight. To calculate normal force, one must draw a free body diagram and consider the direction of the force.
  • #1
picklepie159
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Homework Statement


Just a small, little concept that I don't get...

A man is in an elevator. He is on a bathroom scale. When the elevator goes up, the number on the scale increases. When The elevator goes down, it decreases. What does the scale measure?


Homework Equations



If an object is at rest, the Weight Force is equal Normal Force.


The Attempt at a Solution



In class, the teacher said that when th elvator was accelerating down, then the forces added up to an overall downward pull. He added something about Newton's first law, and then concluded the class with a "The scale measures normal force." and "Weight cannot be measured in moving instances" I understand the second quote, but I am confused about what the normal force really is, and how I can calculate it.
 
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  • #2
The Normal force is the contact force acting perpendicular to the 2 objects in contact. The normal force always points toward the object on which it acts, as long as the two surfaces in contact are not physically attached to one another. To calculate it, you need to draw a free body diagram of the man. His weight acts down, and the normal force (the scale reading) acts which way? Then use Newton 2.
 

FAQ: Conceptual question concerning forces and scales and elevators

1. What is the definition of a force?

A force is a push or pull that can cause an object to accelerate or change its motion.

2. How do forces affect the movement of elevators?

Forces play a crucial role in the movement of elevators. The force of gravity pulls the elevator down, while the counterforce of the tension in the elevator cable pulls it up. The control system of the elevator uses these forces to regulate the movement and ensure a smooth ride.

3. How do different scales affect the force required to move an elevator?

The force needed to move an elevator depends on the weight of the elevator and its load, which is determined by the scale. The heavier the elevator, the more force is needed to move it. This is why larger elevators often require more powerful motors.

4. How do forces and scales impact the safety of elevators?

Forces and scales are crucial factors in ensuring the safety of elevators. The weight capacity of an elevator is determined by its scale, and exceeding this capacity can put too much strain on the motor and potentially cause it to fail. Additionally, proper maintenance and regulation of forces are essential for safe elevator operation.

5. How do elevators maintain stability and balance while in motion?

Elevators use a system of counterweights to maintain stability and balance while in motion. These counterweights, along with the control system, ensure that the elevator remains level and does not tilt or sway during movement.

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