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Homework Help: Determine the magnitude ad direction of the vector

  1. Sep 16, 2007 #1
    I am not sure on how to approach this problem:
    Vector A has a negative x component 3.00 units in length and a positive y component 2.00 units in length.
    a) Determine an expression for A (vector w/arrow hat)in unit-vector notation.
    b)Determine the magnitude ad direction of A
    c)What vector B When added to A gives a resultant vector with no x component and a negative y component 4.00 units in length?

    Can you please give me pointers on how to tackle problems such as these as well as what books/solutions/or things I should do, besides from studying, that will HELP me understand physics.
  2. jcsd
  3. Sep 16, 2007 #2


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    Homework Helper

    New to PF? well, questions llike this should probably goto the homework forum... anyway, welcome aboard.

    Re: Vectors
    you are given the x, y porjections of your vector, you are asked to
    a) write your vector A in terms of unit vectors for you coord system (probably x, y-axis) so wanna express [tex]\vec A = a \hat{\vec x} + b \hat{\vec y}[/tex] where [tex]\hat{\vec x}, \hat{\vec y}[/tex] are the unit-vectors in x, y direction. then u r asked to find [tex]|\vec A|[/tex] length of vector and direction (probably means the angle it makes with the positive x-axis). Length of vector you need Pythagoras.
    finally, you are asked to do some vector addition, since you have been given the x, y -comp, that's make it easy to find the required vector B (in component form), and then you can repeat the steps in a) and b) to find things like magnitude and angle for B.
  4. Sep 24, 2007 #3
    effects of unequal charges on protons and electrons

    The charges on the proton and the electron have been found to be equal to a great many decimal places. But what would be the most important result if the charge on the electron were very slightly less than its measured charge? Wasn't there once a theory of gravitation based on this (assumed) difference?
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