arildno



If I knew that I would not be here asking humbly.



SinghRP



Thanks for the explanation, it made things clearer.



Nabeshin



Yes, this question about negative appear in the calculus too, when I subtract the area under the x axes in the integral of a function.

I guess the example can be used with money too, It would be strange to say minus 10 dollars, but if we're talking about a debt we can write for -10 dollars in the bank balance, or just say they were charged 10 dollars.



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In short, the magnitude of a vector always is positive, by a convention. But I can refer to the force like negative, meaning that its direction is reversed of the reference adopted. Just like the example:



If A is a vector that represents a force I can find B, a vector that is a vector representing a force too, and B will be negative.



B = 0 - A



But we don´t use it because it sounds weird.