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Math Help - Vector problem

  1. #1
    s3a
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    Vector problem

    The only part I get is the 2km [NE]. When it says to go 120 towards the right for the 1.5 km vector, I don't know how to manage that exactly or how to connect it to the 2km vector.

    Any help would be GREATLY appreciated!
    Thanks in advance!
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  2. #2
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    Quote Originally Posted by s3a View Post
    The only part I get is the 2km [NE]. When it says to go 120 towards the right for the 1.5 km vector, I don't know how to manage that exactly or how to connect it to the 2km vector.

    Any help would be GREATLY appreciated!
    Thanks in advance!
    Use a coordinate system with the x-axis pointing East and the y-axis pointing North. Then the direction NE is described by the vector \vec v = (1,1).

    Make a sketch.

    You are dealing with a triangle where you know the length of two adjacent sides and the included angle.
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  3. #3
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    Quote Originally Posted by s3a View Post
    The only part I get is the 2km [NE]. When it says to go 120 towards the right for the 1.5 km vector, I don't know how to manage that exactly or how to connect it to the 2km vector.

    Any help would be GREATLY appreciated!
    Thanks in advance!
    2nd part.

    I assume that you are asked to use vectors. According to my previous post the first part of the trip is described by a vector which has the direction (1, 1). This vector should have the length of 2. Therefore the first part is represented by the vector:

    \vec v = \left(\sqrt{2}\ ,\sqrt{2}\right)

    The second part of the trip is described by a vector which points at an angle of -75 to the East direction (=positive x-axis). Therefore the second vector is

    \vec u = 1.5\cdot (\cos(-75^\circ)\ ,\ \sin(-75^\circ)) = (0.388229\ ,\ -1.44889)

    The endpoint of the trip is detremined by the vector

    \vec e = (\sqrt{2}+0.38829\ ,\ \sqrt{2}+(-1.44889)) = (1.80244\ ,\ -0.03468)

    The distance between start point and endpoint is nothing but the length of \vec e

    |\vec e|\approx 1.80277

    Use the coordinates of \vec e to calculate the direction.
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