- #1
italy55
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Homework Statement
http://imgur.com/a/k7fwG
Find the vector magnetic potential at point P1.
Homework Equations
Vector magnetic potential given by:
$$
d \bar{A} = \frac{\mu I d\bar{l'}}{4 \pi | \bar{r} - \bar{r'} | }
$$
The Attempt at a Solution
I split up the problem in 3 parts,
first solve for potential along the x-axis:
$$ A_x= \frac{\mu I }{4 \pi } \int \frac{\mu I d\bar{l'}}{4 \pi | \bar{r} - \bar{r'} | } = \frac{\mu I }{4 \pi } ln(sqrt(2) +1) $$
$$ \bar{r} =(a,a,0) , \bar{r'} = (x',0,0) , \bar{dl'} = \bar{e_x} dx'
$$
second, I guess this one is the same except the sign:
$$ A_y= \frac{\mu I }{4 \pi } \int \frac{\mu I d\bar{l'}}{4 \pi | \bar{r} - \bar{r'} | } = - \frac{\mu I }{4 \pi } ln(sqrt(2) +1) $$
in the first one, I put $$ \bar{r} =(a,a,0) , \bar{r'} = (0,y',0) , \bar{dl'} = - \bar{e_y} dy' (wrong??)
$$
-----------------
My questions is about the vector differential displacement $$ \bar{dl'} $$, how does the vector differential displacement change between the first, second and the third one?
I'm confused in this part because my formula sheet says that $$ \bar{dl'} = \bar{e_x} dx + \bar{e_y} dy + \bar{e_z} dz $$
How should I think when using the vector differential displacement in the 3 different cases?