Flux of \vec{F} Through S: Compute

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SUMMARY

The discussion focuses on computing the flux of the vector field \(\vec{F} = y\vec{i} + 7\vec{j} - xz\vec{k}\) through the surface \(S\), defined by the equation \(y = x^2 + z^2\) with the constraint \(x^2 + z^2 \leq 36\). The solution involves evaluating the integral \(\int\int_R ((x^2 + z^2)\vec{i} + 7\vec{j} - zx\vec{k}) \cdot (-2x\vec{i} - 2z\vec{k} + \vec{j}) dA\), where \(R\) is the disk in the \(xz\) plane. The discussion emphasizes the importance of the orientation of the unit normal vector to \(S\) and suggests converting to polar coordinates for simplification.

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Homework Statement



Compute the flux of the vector field, [tex]\vec{F}[/tex] , through the surface, S.
[tex]\vec{F} = y\vec{i} + 7\vec{j} - xz\vec{k}[/tex] and S is the surface [tex]y = x^2 + z^2[/tex] with [tex]x^2 + z^2 \leq 36[/tex] oriented in the positive y direction.

Homework Equations





The Attempt at a Solution



[tex]\int\limit_R ((x^2+x^2)\vec{i} + 7\vec{j} - zx\vec{k}) \cdot (-2x\vec{i} -2z\vec{k} + \vec{j})dA[/tex]
 
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Are you trying to evaluate

∫∫R ( (x2+z2) i + 7 j - zx k ) · (-2x i + j -2z k) dA

where R is the disc x2 + z2 ≤ 36 in the xz plane?

So take the dot product, then convert to polar coordinates in the xz plane, is this what you mean?

I think this is correct if the unit normal to S is pointing "right" (i.e., into the parabolic bowl), but negate it if the unit normal to S is pointing "left" (i.e., out of the bowl). Also, you are assuming the bowl has no "lid."
 
thanks!
 

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