Understanding the Sign of 'g' and 'a': An Apparent Weight Example

[Doc Al]

Finally! This equation makes sense! Why didn't you just write this in the first place? ;)

Actually, I did:

If you insist, then apply Newton's 2nd law as a vector equation. It's the same derivation:
∑F = mg + Fn

Set that equal to ma:
mg + Fn = ma

(I used bold to represent vectors.)

 

[Maxo]

When a discussion like this drifts to new confusing questions such as possible "signs of vectors", the side track should be discouraged. Maxo should have been told that vectors usually don't have signs, and if he insists on them having them, that would be a new concept which would require a new definition. Writing down a definition for this new concept would not help in the original problem though.

I agree that would have been good if I had been told that. I wish I would have been able to formulate myself that was in fact was I was asking for already in the beginning but I guess I couldn't see it from such a "meta" perspective when I was struggling in the middle of the question so to speak.

Anyway it's an interesting pedagogical analysis and if you could find some way to implement this way of thinking on the forum, in schools/universites and/or generally I would welcome that. I would like to help with this if possible, if you have some further ideas on the subject please share them on the forum (perhaps in a new thread since it's off topic here) or on in a private message.

Anyway. The original question has been solved. Carry on, gentlemen!