Frequently Made Errors in Mechanics: Forces - comments

[haruspex]

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!

 

[robphy]

In my experience,
the errors I listed are much more frequent than any of the ones you listed.

 

[haruspex]

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.

 

[haruspex]

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.

 

[mechgenesis]

Thanks a lot this was really helpfull