# Another vector problem (smart person please!)

1. Sep 11, 2006

### dboy83

I know this is easy for you smart people, but I need some help. The magnitudes of the four displacement vectors shown in the drawing are A= 16.0 m, B=11.0 m, C=12.0 m ,and D=26.0 m. Determine the magnitude and directional angle for the resultant that occurs when these vectors are added together. * I drew a picture of the problem using paint *
Thanks! You guys are awesome!

#### Attached Files:

• ###### 42.GIF
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2. Sep 11, 2006

Actually, you don't need a smart person. All you need is a google image search named 'vector addition', which will surely help.

3. Sep 11, 2006

### HallsofIvy

Could some of us "dumb folks" help? You understand, don't you, that a vector depends upon direction as well as length and so the sum of two or more vectors depends on the angle of each vector as well as the length.

4. Sep 11, 2006

### dboy83

Yes, I know that much. This problem is much different than the ones I'm used to working out by using pythagorean theorem. What is the next step?

5. Sep 11, 2006

### Staff: Mentor

Your attachment is still pending approval, but I'll give you a hint in case it helps. It sounds like you are given the vectors in polar notation (magnitude and direction). You will need to convert them into rectangular notation (deltaX,deltaY) in order to more easily add them. You can then convert the resultant back into polar form if it seems like the problem is asking for the resultant in magnitude, direction format.

What formulas should you use to convert back and forth between the two different vector representations? Oh, and in the latest smart person competition among the Homework Helpers, I was near the bottom.

EDIT -- fixed a typo