Simple Vector Problem - Finding the x-component

  • Thread starter Nulligan
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  • #1
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Homework Statement



A velocity vector 45 below the positive x-axis has a y-component of - 29 .
What is the value of its x-component?

Homework Equations



Vx = |V|Cos(Theta)
Vy = |v|Sin(Theta)

The Attempt at a Solution



Theta = -45 degrees
y-component: -29 = xSin(-45) .... where x is the magnitude of the vector

x = Sin(-45) / - 29
...x = 0.2438

So |V| = 0.24~

Vx = (0.24)Cos(-45)
...=0.171

Says it's wrong, and I dont know where to go now. Am a bit embarassed asking for help with a simple problem like this :\
 

Answers and Replies

  • #2
6
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Oops sorry, nevermind, I realised that in Step 2 I should have divided by Sin(-45)

apologies!
 
  • #3
6
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Homework Statement



Find x- and y-components of the following vectors
v = 7.0 cm/s, negative x-direction

Homework Equations



Vx = |V|Cos(Theta)
Vy = |v|Sin(Theta)

The Attempt at a Solution



I'm a bit stuck here. I slotted in 7cm/s for |v| but how do I find the components if I'm not given an angle or graphical representation?
 
  • #4
Dick
Science Advisor
Homework Helper
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It says 'negative x direction'. I think that means it points along the x-axis in the, uh, 'negative' direction. Are you sure you don't want to rethink posting this question?
 
  • #5
6
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I thought of that after I posted it and came up with -1, 0 as the x,y components [using cos180 and sign 180) which was still wrong. it's late so I wasn't thinking clearly :P
 

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