Adding vectors in this 3-D problem

[huehuephy]

Homework Statement

Hi! I'm having a problem trying to figure out a 3D vector physic question. Some help would be appreciated!

Relevant Equations

Three vectors all have the same magnitude. The symbol for the magnitude of each of these vectors is M. The first vector points in the positive x direction. The second vector points in the negative y direction. The third vector points in the positive z direction. These three vectors added together are equal to a fourth vector . What is the magnitude of the fourth vector?

I gathered that the final position of the vectors when added up would be (M,-M,M), but I'm not sure if this is correct.

 

[berkeman]

Homework Statement:: Hi! I'm having a problem trying to figure out a 3D vector physics question. Some help would be appreciated!
Relevant Equations:: Three vectors all have the same magnitude. The symbol for the magnitude of each of these vectors is M. The first vector points in the positive x direction. The second vector points in the negative y direction. The third vector points in the positive z direction. These three vectors added together are equal to a fourth vector . What is the magnitude of the fourth vector?

I gathered that the final position of the vectors when added up would be (M,-M,M), but I'm not sure if this is correct.

Yes, that is one way to represent the resultant vector. The problem asks you for the magnitude of the result of adding those components. Can you change the representation of the resultant vector sum into <Magnitude,Direction> format? (and you don't need to figure out the direction part of it for this problem)

It probably also helps to draw a sketch of adding those 3 vectors nose-to-tail...

 

[Chestermiller]

Are you familiar with the Pythagorean therom?