Is Any Applied Force Truly a Normal Force?

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Discussion Overview

The discussion revolves around the statement made by a teacher that "any applied force can also be called a normal force." Participants are examining the validity of this assertion, particularly in the context of forces acting on objects in a plane, and the conditions under which a force can be classified as a normal force.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Technical explanation

Main Points Raised

  • Some participants suggest that an applied force cannot be considered a normal force if it acts in the same plane as the object, implying that a normal force must act perpendicular to the surface.
  • One participant proposes that a normal force can be applied from a direction perpendicular to a surface, while also questioning the interpretation of forces in different planes.
  • Another participant emphasizes that the normal force is defined as the force perpendicular to a surface, which pushes back against an applied force, and notes that this relationship holds true only when the applied force is perpendicular to the surface.
  • There is a reiteration of Newton's third law, stating that an object pushes back with an equal and opposite force when acted upon, which is relevant to understanding normal forces.

Areas of Agreement / Disagreement

Participants express differing views on the definition and conditions of normal forces, indicating that there is no consensus on the teacher's statement. The discussion remains unresolved with multiple competing interpretations of what constitutes a normal force.

Contextual Notes

Some participants express uncertainty about the terminology used, such as "Z plane," and the implications of forces acting in different directions relative to surfaces. There are also references to specific examples, like forces acting on a circle, which may not fully clarify the broader concept.

Sandy_221
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THIS IS THE QUESTION:

Your teacher says, “Any applied force can also be called a normal force.” Discuss the validity of this statement.


Thanks guys.
 
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Sandy_221 said:
THIS IS THE QUESTION:

Your teacher says, “Any applied force can also be called a normal force.” Discuss the validity of this statement.


Thanks guys.

No, YOU discuss the validity of this statement and ask questions if you are not sure about the validity of any of the points in your discussion. We are not here to do your homework for you.

Please read the forum rules for posting homework.
 
I think if the object that is acted upon is on the the X-Y plane, for example, then an applied force can't be considered a normal force if the former is in the same plane as the latter. In order for an applied force to be a normal force it has to be on the Z plane.

Is this right?

What do you think, guys?
 
Last edited:
I may not be following exactly what you're saying, but if I understand it, an example what you are describing would be a circle (a flat disk) in the XY plane. If that's the case, then a normal force could be one that is applied straight onto the disk from the Z direction (I don't understand what you mean by the "Z plane") OR it could be one that is applied normal to the circle from a direction in the XY plane.

If I've misunderstood the question, please set me straight and I'll have another think.
 
Let me put in an observation.

The "normal" force is the force perpendicular to any surface with which the surface "pushes back".

Furthermore, if you push against an object, the object pushes back with exactly the same force in the opposite direction (Newton's third law).

In other words, if you push against an object perpendicular to its surface, the normal force pushes back with the same force but in opposite direction.

However, if you do not push perpendicular to the surface, this is not true.
 
I like Serena said:
Let me put in an observation.

The "normal" force is the force perpendicular to any surface with which the surface "pushes back".

Furthermore, if you push against an object, the object pushes back with exactly the same force in the opposite direction (Newton's third law).

In other words, if you push against an object perpendicular to its surface, the normal force pushes back with the same force but in opposite direction.

However, if you do not push perpendicular to the surface, this is not true.

Yes, that is exactly what I had in mind. The force towards the edge of the circle WOULD have to be towards the center and I did neglect to state that.

Do you see any issue w/ my response?
 

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