2-D Vectors

Key Questions

  • A quantity possessing both magnitude and direction, represented by an arrow the direction of which indicates the direction of the quantity and the length of which is proportional to the magnitude.

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  • Resultant of vectors can be found using the law of cosines.

    If A and B are two vectors with an angle between them equal to #theta# (#theta < pi#), their resultant R is given by,

    #R = [A^2 + B^2 + 2AB Cos theta]^(1/2)#, this gives the magnitude of R.

    If the vector R makes an angle #alpha# with vector A, then

    #alpha = arctan [(B Cos theta)/(A + B Sin theta)]#