# Flux

• Jun 8th 2009, 08:11 AM
Apprentice123
Flux
Since the field vectors $F(x,y,z) = xi +0j +zk$ and the cylinder obtained by rotation the straight: $x=1; y=t; z=0$ with $-1 \leq t \leq 1$ around the axis OY. Determine the flow of the field F in the direction normal outside of the cylinder

My solution:

Rotating

$F(r(t,u)) = (cosu,t,sinu)$

normal: $N = (\frac{ \partial (r)}{ \partial (t)} X \frac{ \partial (r)}{ \partial (u)}) = (cosu,0,sinu)$

$\int_0^{2 \pi} \int_{-1}^1 (cosu,t,sinu).(cosu,0,sinu) = 4 \pi$

It is correct ?
• Jun 8th 2009, 10:48 AM
Apprentice123
It is correct ?