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Math Help - Vectors and relative velocity.

  1. #1
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    Vectors and relative velocity.

    so confusing.here is the question,a man was walking with a velocity 4i km/h when he observed that the wind was blowing from the north.When the man increased his velocity to 6i km/h,he noticed the wind seemed to be blowing from N45W.Find the velocity and direction of the wind.
    I can't figure out how to solve it even though i tried it many times.the answer is 4.472km/h N63.43E
    Last edited by mr fantastic; September 3rd 2011 at 12:14 AM. Reason: Re-titled.
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  2. #2
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    Re: Vector!please help me.

    What have you tried? Did you get that his perception of the wind is the resultant of his velocity and the constant wind velocity? It is only his perception that changes.
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  3. #3
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    Re: Vector!please help me.

    no.this may be due to his relative velocity to the wind.but,i couldn't find the magnitude out.
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  4. #4
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    Re: Vector!please help me.

    Ok.Finally, i found it.when man was walking 4i km/h to east,the wind appeared blowing from north.velocity of wind=(xi,yj),velocity of man=(4i,0j),when he felt,means him observed.so,relative velocity=(0i,aj),=(x-4,yj).So x=4.when wind flow from north west 45,velocity of wind=(xi,yj),velocity of man=(6i,0j),relative velocity=(x-6,y),tan45=(-4+6)/a,y=2,magnitude=square root of(4^2+2^2)
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  5. #5
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    Re: Vectors and relative velocity.

    You did NOT say, before, that the man was walking to the East! Where did that come from?
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