Frequently Made Errors in Mechanics: Forces - comments

Click For Summary
SUMMARY

The forum discussion centers on common misconceptions in mechanics, particularly regarding forces and their properties. Key points include the misunderstanding of "line of action" and its significance in force application, as well as the confusion surrounding tension in strings. Participants emphasize that a force is defined by its vector and point of application, while the line of action is crucial for understanding moments. The conversation highlights the need for clarity in teaching these concepts to avoid confusion among students.

PREREQUISITES
  • Understanding of basic mechanics concepts, including forces and vectors.
  • Familiarity with tension in strings and its implications in physics.
  • Knowledge of moments and their relation to force application.
  • Basic grasp of vector addition and its common misconceptions.
NEXT STEPS
  • Research the concept of "line of action" in mechanics and its role in force analysis.
  • Study the differences between tension in strings pulled from both ends versus one end.
  • Learn about moments and how they relate to the point of application of forces.
  • Examine common errors in vector addition and how to correct misconceptions in physics education.
USEFUL FOR

This discussion is beneficial for physics educators, students studying mechanics, and anyone interested in clarifying fundamental concepts of forces and their applications in physics.

  • #31
robphy said:
Here are other common errors...
1) "the magnitude of the normal force is always mg" (because of a formula they saw).
2) "the magnitude of the static friction force is always \mu_k N" (because of a formula they saw)
3) "the centripetal force is an additional force drawn on a free-body diagram"
Point 3 I have covered in another post under development.
Points 1 and 2 belong in a much more general FME. I'll add them to my list!
 
Physics news on Phys.org
  • #32
In my experience,
the errors I listed are much more frequent than any of the ones you listed.
 
  • #33
haruspex said:
Point 3 I have covered in another post under development.
Points 1 and 2 belong in a much more general FME. I'll add them to my list!
Correction:
Point 2 I have already covered in an imminent post on Friction.
 
  • #34
No, a force is neither a tension nor a compression. A force is something one body exerts on another. Tension and compression usually refer to extensive states within a body. You could describe an action/reaction pair as a compression or a tension, but not the two individual forces.
 
  • #35
Thanks a lot this was really helpfull
 

Similar threads

Frequently Made Errors in Mechanics - Springs - Comments
  • · Replies 3 ·
Replies
3
Views
2K
Undergrad Frequently Made Errors in Mechanics: Hydrostatics - Comments
  • · Replies 2 ·
Replies
2
Views
2K
Frequently Made Errors in Mechanics - Kinematics - Comments
  • · Replies 10 ·
Replies
10
Views
3K
Graduate Frequently Made Errors in Mechanics - Moments - Comments
  • · Replies 6 ·
Replies
6
Views
2K
Frequently Made Errors in Mechanics - Friction - Comments
  • · Replies 7 ·
Replies
7
Views
2K
Undergrad Frequently Made Errors in Mechanics - Momentum and Impacts - Comments
  • · Replies 1 ·
Replies
1
Views
2K
Insights Frequently Made Errors - Pseudo and Resultant Forces - Comments
  • · Replies 12 ·
Replies
12
Views
2K
Graduate Statistical Mechanics Part II: The Ideal Gas - Comments
  • · Replies 11 ·
Replies
11
Views
3K
Graduate Statistical Mechanics Part I: Equilibrium Systems - Comments
  • · Replies 19 ·
Replies
19
Views
3K
Servo-Constraints in Mechanics - Comments
  • · Replies 4 ·
Replies
4
Views
2K