Test Stokes' Theorem for the function

Join the discussion
Registration is free. Ask a follow-up in this thread, or start your own.
1 reply · 8K views
stunner5000pt
Messages
1,447
Reaction score
5
Test Stokes' Theorem for the function
[itex]\vec{v} = (xy) \hat{x} + (2yz) \hat{y} + (3yz) \hat{z} /[/itex]

for the triangular shaded region

[tex]\int_{S} (\grad \times v) \dot da = \oint_{P} v \bullet dl[/tex]

for the left hand side

[tex]\int_{0}^{2} \int_{0}^{2} (-2y \hat{x} - 3z \hat{y} - x \hat{z}) \hat{x} dy dz = \int_{0}^{2} \int_{0}^{2} (-2y) dy dz = \left[ \frac{-y^2} \right]_{0}^{2} \int_{0}^{2} dz = (-4)(2) = -8[/tex]

so far so good??

ok for hte right hand side

i) x=0, z=0, [itex]v \bullet dl = 2y dy[/itex] integration limits 0 to 2

ii) x=0, y=2, [itex]v \bullet dl = 0 dz[/itex] integration from 0 to 2

i am not sute about the last one though...

am i right with i and ii though??

thank you for any advice!
 

Attachments

  • noise.JPG
    noise.JPG
    8.1 KB · Views: 1,282
Last edited by a moderator:
Physics news on Phys.org
stunner5000pt said:
Test Stokes' Theorem for the function
[itex]\vec{v} = (xy) \hat{x} + (2yz) \hat{y} + (3yz) \hat{z} /[/itex]

for the triangular shaded region

[tex]\int_{S} (\grad \times v) \dot da = \oint_{P} v \bullet dl[/tex]

for the left hand side

[tex]\int_{0}^{2} \int_{0}^{2} (-2y \hat{x} - 3z \hat{y} - x \hat{z}) \hat{x} dy dz = \int_{0}^{2} \int_{0}^{2} (-2y) dy dz = \left[ \frac{-y^2} \right]_{0}^{2} \int_{0}^{2} dz = (-4)(2) = -8[/tex]

so far so good??
No, your [itex]\nabla \vec{v}[/itex] is wrong. The [itex]\hat{y}[/itex] component is 0.

ok for hte right hand side

i) x=0, z=0, [itex]v \bullet dl = 2y dy[/itex] integration limits 0 to 2
That should be [itex]v \bullet dl= 2yz dy= 0[/itex]

ii) x=0, y=2, [itex]v \bullet dl = 0 dz[/itex] integration from 0 to 2

i am not sute about the last one though...
for the last one, you can take y= t, z= 2- t integrating from t= 0 to 2.

am i right with i and ii though??

thank you for any advice!
By the way, to get [itex]\nabla[/itex] use "\nabla", not "\del".