/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 16 Find the net outward flux of \(\... [FREE SOLUTION] | 91Ó°ÊÓ

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Find the net outward flux of \(\mathbf{F}=\mathbf{a} \times \mathbf{r}\) across any smooth closed surface in \(\mathbb{R}^{3}\), where a is a constant nonzero vector and \(\mathbf{r}=\langle x, y, z\rangle\)

Short Answer

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#tag_title#Step 2: Calculate the Divergence of \(\mathbf{F}\)# #tag_content#Now let's calculate the divergence of the vector field \(\mathbf{F}\). The divergence of a vector field \(\mathbf{G}\) with components \(G_x, G_y, G_z\) is given by \(\nabla \cdot \mathbf{G} = \frac{\partial G_x}{\partial x} + \frac{\partial G_y}{\partial y} + \frac{\partial G_z}{\partial z}\). Applying this to our vector field \(\mathbf{F}\), we get: $$ \nabla \cdot \mathbf{F} = \frac{\partial}{\partial x}(a_yz - a_z y) + \frac{\partial}{\partial y}(a_zx - a_x z) + \frac{\partial}{\partial z}(a_x y - a_y x) $$ Differentiating with respect to each variable, we have: $$ \nabla \cdot \mathbf{F} = 0 - a_z +a_x - a_y + 0 + 0 = - (a_z + a_y) + a_x $$ #tag_title#Step 3: Apply the Divergence Theorem# #tag_content#Now that we have the divergence of \(\mathbf{F}\), we can use the divergence theorem to find the net outward flux. Recall that the divergence theorem states: $$ \iint_{S} \mathbf{F} \cdot \mathbf{\hat{n}} dS = \iiint_{V} \nabla \cdot \mathbf{F} dV $$ Since the divergence is constant (it does not depend on \(x, y, z\)), we can write: $$ \iint_{S} \mathbf{F} \cdot \mathbf{\hat{n}} dS = \iiint_{V} (-a_y - a_z + a_x) dV $$ Since we know the volume of the enclosed region \(V\), we can write this as: $$ \iint_{S} \mathbf{F} \cdot \mathbf{\hat{n}} dS = (-a_y - a_z + a_x) \cdot \mathrm{Volume}(V) $$ To summarize, the net outward flux of the vector field \(\mathbf{F}\) across any smooth closed surface in \(\mathbb{R}^{3}\) is given by the expression \((-a_y - a_z + a_x) \cdot \mathrm{Volume}(V)\).

Step by step solution

01

Cross Product of \(\mathbf{a}\) and \(\mathbf{r}\)#

Given a constant nonzero vector \(\mathbf{a}= \langle a_{x}, a_{y}, a_{z}\rangle\) and the position vector \(\mathbf{r}=\langle x, y, z \rangle\), the cross product of \(\mathbf{a}\) and \(\mathbf{r}\) is: $$ \mathbf{F} = \mathbf{a} \times \mathbf{r} = \begin{vmatrix} \mathbf{i} & \mathbf{j} & \mathbf{k} \\ a_x & a_y & a_z \\ x & y & z \end{vmatrix} $$ Expanding this determinant, we get: $$ \mathbf{F} = \langle a_yz - a_z y, a_zx - a_x z, a_x y - a_y x \rangle $$

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Most popular questions from this chapter

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