Calculate Flux of Vector Field in Closed Surface | Divergence Problem Solution

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In summary, the question asks to find the flux of the vector field, F = x^3 + y^3 + z^3, out of a closed surface that bounds a solid region defined by x^2 + y^2 ≤ 16 and 0 ≤ z ≤ 9, oriented outward. The solution involves finding the divergence of the vector field, which is 3x^2 + 3y^2 + 3z^2, and using the divergence theorem to integrate over the surface using cylindrical coordinates.
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luju
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Homework Statement



Find the flux of the vector field out of the closed surface bounding the solid region x^2 + y^2 ≤ 16, 0 ≤ z ≤ 9, oriented outward.

F = x^3 + y^3 + z^3


Homework Equations





The Attempt at a Solution


I found the divergence which is 3x^2+3y^2+3z^2.

And then I'm stuck. I know Flux is divergence * Volume, in a simplifed way. So i factored 3 out, and i got 3(x^2+y^2) + 3z^2. I do not know where to go from here. Thanks in advance
 
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Integrate over the surface using the transformation to cylindrical co-ordinates, using x = square_root(16) cos(theta) and similarly for y, and the divergence theorem gives support to your integrating over the vector field, once you have added in the jacobian, from zero to two pi for theta, and from zero to 9 for z.
 

1. What is the meaning of flux in vector fields?

Flux refers to the flow of a vector field through a given surface. It represents the amount of the vector field passing through the surface at a given point.

2. How do you calculate the flux of a vector field in a closed surface?

The flux of a vector field through a closed surface can be calculated by using the divergence theorem, which states that the flux is equal to the volume integral of the divergence of the vector field over the enclosed volume.

3. What is the purpose of solving a divergence problem in calculating flux?

Solving a divergence problem is necessary in order to accurately calculate the flux of a vector field through a closed surface. The divergence problem involves finding the divergence of the vector field, which is a measure of how much the vector field is "spreading out" or "converging" at a given point. This information is crucial in determining the flux through the surface.

4. What is the significance of a closed surface in calculating flux?

A closed surface is important in calculating flux because it provides a boundary for the volume over which the flux is being calculated. The divergence theorem can only be applied to a closed surface, as it requires a complete boundary for the enclosed volume.

5. Can you provide an example of calculating the flux of a vector field in a closed surface?

Sure, let's say we have a vector field F = (xy, yz, zx) and we want to calculate the flux through a closed cube with sides of length 2 centered at the origin. First, we find the divergence of the vector field, which is 2x + y + z. Then, using the divergence theorem, we can calculate the flux as the volume integral of the divergence over the enclosed cube, which would give us a value of 16.

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