Register to reply

Seemingly simple

by Phymath
Tags: seemingly, simple
Share this thread:
Phymath
#1
Sep5-05, 08:43 PM
P: 186
ok well basicly use the divergence thrm on this..
[tex]
\vec{v} = rcos\theta \hat{r} + rsin\theta\hat{\theta} + rsin\theta cos \phi \hat{\phi}[/tex]

so i did (remember spherical coords) i get..
[tex] 5cos \theta - sin\phi[/tex]
taking that over the volume of a hemisphere resting on the xy-plane i get [tex]10R \pi[/tex]

however with the surface intergral i use [tex] d\vec{a} = R^3 sin\theta d\theta d\phi \hat{r}[/tex] where R is the radius of the sphere doing that intergral gives me something obvioiusly R^3 which is not what I'm getting in the volume intergral any help or explainations (if its i need to take the surface of the bottom of the hemi sphere aka the xy-plane in a circle that will suck but let me know!
Phys.Org News Partner Science news on Phys.org
'Smart material' chin strap harvests energy from chewing
King Richard III died painfully on battlefield
Capturing ancient Maya sites from both a rat's and a 'bat's eye view'
Reshma
#2
Sep6-05, 08:57 AM
P: 777
however with the surface intergral i use [tex] d\vec{a} = R^3 sin\theta d\theta d\phi \hat{r}[/tex] where R is the radius of the sphere doing that intergral
Your surface integral is wrong.
[tex] d\vec{a} = R^2 sin\theta d\theta d\phi \hat{r}[/tex] not R3.


Register to reply

Related Discussions
Seemingly simple problem Set Theory, Logic, Probability, Statistics 7
Seemingly simple question. Chemistry 1
Seemingly simple proof I can't seem to get Calculus & Beyond Homework 8
Seemingly simple, what am i doing wrong? Introductory Physics Homework 6
Seemingly Simple... General Math 7