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Calculate Electric field from two point charges 
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#1
Feb1208, 11:31 AM

P: 37

1. The problem statement, all variables and given/known data
Two point charges with q1=2x10^5 and q2=4x1^3 are located in free space at (1,3,1) and (3,1,2), respectively, in a cartesian coordinate system. Calculate the electric field E at (3,1,2) 2. Relevant equations E=(1/4piE0)(qr1/r1^3+qr2/r2^3) 3. The attempt at a solution I understand the above equation but am unsure of how to implement it using cartesian coords? 


#2
Feb1208, 12:22 PM

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PF Gold
P: 4,982

The distance between two points is:
[tex] s = \sqrt{(x_1x_2)^2+(y_1y_2)^2+(z_1z_2)^2} [/tex] 


#3
Feb1208, 01:02 PM

P: 37

how do i use the vector in this part of the equation though?
q1r1/r1^3 the r1 on top is still a vector... and then i presume for the bottom part i just take the magnitude of r1 and cube it? 


#4
Feb1208, 01:57 PM

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Calculate Electric field from two point charges
Well I've given you the magnitude of the vector so what do you imagine its components to be?



#5
Feb1208, 02:02 PM

P: 37

just (x,y,z) surely?



#6
Feb1208, 02:08 PM

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Make that: [itex] ((x_1x_2) \mathbf{\hat{i}}+.....) [/itex] etc.



#7
Feb1208, 02:32 PM

P: 37

Awesome, thanks!



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