Vector direction help

  • Thread starter teffy3001
  • Start date
  • #1
23
0
ive been trying to do this problem but i dont know where to start....any help?


let v be a vector of length 9 in the direction 65degrees south of west.

if u has the same direction as v, and if 3|u| = 2|v|, then which of the following can be used to describe u?


u = 5.705i + 12.235j
u = -2.536i - 5.438j
u = 2.536i + 5.438j
u = -5.705i - 12.235j
none of these
 

Answers and Replies

  • #2
radou
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  • #3
23
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no im not sure....cause im not even sure how to get started on this question...
 
  • #4
radou
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no im not sure....cause im not even sure how to get started on this question...

Draw your vector v down, first. Do you know anything about projections on the x and y axis?
 
  • #5
23
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yeah
i think i have to find the components of u but using the magnitude of v..is that right?
 
  • #6
radou
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6
yeah
i think i have to find the components of u but using the magnitude of v..is that right?

First of all, you have to write down v in the form v = ___ i + ___ j. Then, you know that 3|u| = 2|v|, eg |u| = 2/3|v|.
 
  • #7
23
0
okay thanks i think i got it now : )
 

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