# Determine the magnitude ad direction of the vector

1. Sep 16, 2007

### innightmare

I am not sure on how to approach this problem:
Question:
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.
Thanks!

2. Sep 16, 2007

### mjsd

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 $$\vec A = a \hat{\vec x} + b \hat{\vec y}$$ where $$\hat{\vec x}, \hat{\vec y}$$ are the unit-vectors in x, y direction. then u r asked to find $$|\vec A|$$ 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.

3. Sep 24, 2007

### elprospero

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?
Elprospero@dslextreme.com

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