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Active Calculus - Multivariable

Activity 13.10.3. Checking the Visualization for Flux.
(a)
Figure 13.10.12 shows a plot of the vector field \(\vF=\langle{y,z,2+\sin(x)}\rangle\) and a right circular cylinder of radius \(2\) and height \(3\) (with open top and bottom). Consider the vector field going into the cylinder (toward the \(z\)-axis) as corresponding to positive flux.
Figure 13.10.12. The vector field \(\vF=\langle{y,z,2+\sin(x)}\rangle\) and a right circular cylinder
(i)
Reasoning graphically, do you think the flux of \(\vF\) throught the cylinder will be positive, negative, or zero? Write a few sentences jutifying your answer.
(ii)
Parameterize the right circular cylinder of radius \(2\text{,}\) centered on the \(z\)-axis, for \(0\leq z \leq 3\text{.}\) Be sure to give bounds on your parameters.
(iii)
Based on your parameterization, compute \(\vr_s\text{,}\) \(\vr_t\text{,}\) and \(\vr_s \times \vr_t\text{.}\) Confirm that these vectors are either orthogonal or tangent to the right circular cylinder. Is your orthogonal vector pointing in the direction of positive flux or negative flux?
(iv)
Use your parametrization to write \(\vF\) as a function of \(s\) and \(t\text{.}\)
Hint.
The \(x\)-coordinate is given by the first component of \(\vr\text{.}\)
(v)
Compute the flux of \(\vF\) through the parameterized portion of the right circular cylinder.
(vi)
Does your computed value for the flux match your prediction from earlier?
(vii)
Use Figure 13.10.13 to make an argument about why the flux of \(\vF=\langle{y,z,2+\sin(x)}\rangle\) through the right circular cylinder is zero.
Figure 13.10.13. The vector field \(\vF=\langle{y,z,2+\sin(x)}\rangle\) with normal and tangential components plotted on a right circular cylinder
(b)
Write a couple of sentences to explalin how the results of the flux calculations would be different if we used the vector field \(\vF=\left\langle{y,z,\cos(xy)+\frac{9}{z^2+6.2}}\right\rangle\) and the same right circular cylinder.
(c)
write a couple of sentences to explain how the results of the flux calculations would be different if we used the vector field \(\vF=\langle{y,-x,3}\rangle\) and the same right circular cylinder.