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Grade 12, Vector Addition

  • Thread starter jord12321
  • Start date
  • #1
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Homework Statement


A plane heads 20° north of east at 200 m/s. The wind blows 60° north of east at 50 m/s. What is the resultant velocity of the plane?


Homework Equations


Δv= v2-v1 or Δv= v2+(-v1)


The Attempt at a Solution


I know you have to solve for the x and y, but I don't know how to do that. Then I know once you get your two answers, you use pythagorean theorem to get the final answer.
 

Answers and Replies

  • #2
gb7nash
Homework Helper
805
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First off, every vector in 2D has an x component and a y component. How do you find the x and y component for a given vector?
 
  • #3
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You use sinΘ or cosΘ, and then you times that number by the velocity.
 
  • #4
gb7nash
Homework Helper
805
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You use sinΘ or cosΘ, and then you times that number by the velocity.
Ok...so do it and show what the x and y components are of the plane and the wind.
 
  • #5
559
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Once you get what he says add the x components and y components vectorally.
 
  • #6
13
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So my total for x was 111 and for y it was 213. So then I used pythagorean theorem and got 240. I'm not sure if this is correct though. And then for my angle i got 62.5
 
  • #7
gb7nash
Homework Helper
805
1
So my total for x was 111 and for y it was 213. So then I used pythagorean theorem and got 240. I'm not sure if this is correct though. And then for my angle i got 62.5
You got your sin and cos mixed up. x = rcosΘ and y = rsinΘ. Besides that, do what you were doing.

Also, in the future, show your work. I'm lucky to have a calculator handy, so I can tell where you made your mistake, but it's easier to follow your work than trying to decipher what you did.
 

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