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**1. Homework Statement**

I'm working with some 3-D vectors, which I'm a bit unsure about. I may have more of a clue than I think, but I could use a bit of assistance. So...

I'm dealing with two particles, A and B. A is on the x-y plane where x=y (*corrected: this was mistyped as x=7 when originally posted; it should be x=y) and is 20 meters from the origin, while B is on the y-z plane where y=z and is 40 meters from the origin. Write the two position vectors A and B in terms of their components, and the same for the displacement vector R that goes from A to B. Then, write a force vector F with magnitude 20 Newtons and pointing from A to B (also in component form).

**3. The Attempt at a Solution**

My initial and probably primary issue with this problem is determining where these two points are. I presume in digging through my thoughts that A is at point (20, 20, 0) and B (0, 40, 40). That would mean that my components are (for A) 20i + 20j and (for B) 40j + 40k. I'm not positive about this, though, and I'd appreciate some advice. As for the force vector, I realize I need to use (create) a unit vector to do this, but how do I create a vector that is in this 3-D form? My thought is that I could do this when I have the other vector components, but how do I use the magnitude (20 Newtons) in order to solve this?

Thank you for any assistance!

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