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# Vectors watch

1. Don't understand the question and can't make sense of the diagrams given.

I know OA = (xi,0,0) however don't know how to use info given in bottom part of the question
2. Explanation of diagrams: there's a pole sticking up vertically. There are three "cables" attached to it, spread evenly with angles of 120 degrees. They are distance from the pole. The vectors and are shown on the plan view.

If you still don't get it, the answer to part (a) is in the spoiler below.
Spoiler:
Show

3. Oh, didn't see the last sentence you said. Did you edit that in after I started writing my reply? Sorry, ignore the above post.

Do you mean part (c)? If so then think of dot products.
4. (Original post by TLDM)
Explanation of diagrams: there's a pole sticking up vertically. There are three "cables" attached to it, spread evenly with angles of 120 degrees. They are distance from the pole. The vectors and are shown on the plan view.

If you still don't get it, the answer to part (a) is in the spoiler below.
Spoiler:
Show

How did you get -1/2x and sqrt(3)/2?
5. (Original post by TSRforum)
How did you get -1/2x and sqrt(3)/2?
Trigonometry. You can find the angle between and , and you also know that has length . You should be able to work it out from there.

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