Recent content by mr.hood

Hi all, I've been trying to figure out how I can use the Scanner class in Java to pause my program and wait for the user to hit the return key. What I have now looks like this: Scanner kbd = new Scanner(System.in); kbd.next(); ... The thing is, the rest of my program won't run unless there...

Homework Statement A uniformly charged sphere (center O1) with radius a and charge +Q has an off-center cavity within it (center O2) with radius b. Show that the electric field within the cavity is uniform and is directed along the line of centers, according to the equation: \vec{E} =...

Scrap that last post, I treated this problem with sort of a surface integral and got an answer (an admittedly strange-looking one): First I used the equation: \vec{E} = \frac{1}{4\pi\epsilon_{o}} \int_{S}\frac{\sigma(\vec{r'})}{r^{2}}\hat{r}da' Part (a): \vec{E} =...

Easy enough, thanks for the help! Edit: Haha not so easy I guess... I set up the following integral (for part (a)): \vec{E} = \frac{2\sigma}{4\pi\epsilon_{o}a}\int^{-a/2}_{a/2}\frac{dx}{x}\hat{x} When I integrate the 1/x from a/2 to -a/2, I of course get zero. Is my integrand...

Thanks, you're a life saver!

So I accidentally set my skin to "mobile," and now I can't figure out how to change it back because the "options" links no longer shows up in My PF. Help??

Ok, so I guess I can treat the ribbon like a line of charge when I'm looking at it from a point on the x-axis... And is it safe to assume I should integrate across the width of the ribbon as well, because of the contributions of all the charge "behind" the edge I'm looking at? I would think I...

Homework Statement A long uniformly charged ribbon is located in the x-z plane, parallel to the z axis, occupying the region -\infty \leq x \leq \infty and -a/2 \leq x \leq a/2. The charge per unit area on the ribbon is \sigma. a) Determine \vec{E} at (x,0,0) where x > a/2. b) Determine...