Physics experiment (1 Viewer)

[Le3sah]

Hey:wave:

Has anyone done the experiment involving a perspex rod and a pith ball? If you have, can you please tell me why the ball repels the rod when held close, BUT when actually placed so that they touch they attract? I'm not even sure if thats the behaviour? Most my practicals turn out wrong . (I'm aware that the sentences above made absolutely no sense... )

..So if you understand me lol, can you please explain the theory behind all of that?

Any help would be great! Thanks heaps in advance!!

 

[cfair]

don't do physics but i think i can help you, this is coulomb's law right?

 

[cdiz]

Perspex rods are fun.

 

[Le3sah]

don't do physics but i think i can help you, this is coulomb's law right?

I'm not sure, I wasn't there for the stupid prac but I still have to write it!
I assume it's coulombs.. lol, but yes any help would be great

Ebonite rods are fun too.

 

[cfair]

yeah it is from the look of it, coulombs law is 'The electrical force of one body exerted on the second body is equal to the force exerted by the second body on the first.'

That's the only theory behind it you need to write right? I don't know how you write up your physics pracs so if you need a page you're fresh outta luck and jolly well fucked .

 

[Le3sah]

Okay, i'll add that in somewhere.
I guess i'm just going to have to bullshit myself one page. Its been done before.

Thanks heaps Cal!

 

[cfair]

thats ok, you owe me, i have another 'task' for you once you get on msn hahahaha

 

[z600]

I am assuming u have rubbed your perspex rod with some sort of a fabric.
When you rub the rod with a piece of fabric you charge the perspex, the perspex is now positively charged. I dono what exactly what the "pitch ball" is made out of, but from the sound of it, it's also positively charged (like charges repell) and i have no idea what you mean by they attrach....

 

[nelses]

uh well a perspex rod becomes positively charged when rubbed with silk and if the pith ball? is neutral, then a charged object will attract towards the electrons in the neutral object. I think after they touch the positive charge is shared over the two objects causing the neutral to become positively charge and having them repel each other? not sure if this answers your question though.