Question

I have a question regarding charges, and electric fields. My problem goes like this....
"Sphere A has a charge of +64microC, and is positioned at the origin. A second charge, Sphere B, has a charge of -16microC and is placed at +1.00 meters on the x-axis. Where must a third sphere, C, of charge +12microC be placed so there is no net force on it?"
... My question is simple: how do I figure this out?!

Any and all help is greatly appreciated! :)

Answer 1

Have you learnt the concept of Fields? or are you just working with forces.. (either one will do)

Answer 2

I've learned about both, but am just unsure of how to go about you know... calculating the placement of a third charge in relation to these to have a net force of 0.

Answer 3

If force should be zero, then the field must be zero

so think..
imagine a plus charge.. and a minus charge (plus charge having greater magnitude).. where do you think in space could the field be zero?

Answer 4

To the right of both charges, right?

Answer 5

mark it in the drawing plz :P (just to make sure we are on the same page)

Answer 6

no intended pun xD

Answer 7

I apologize, but I'm on an iPad, using safari of all things, and thus certain features of OS are unavailable to me... Like the equations typer and drawings... I made this instead !
http://www.twiddla.com/1504676
I feel quite certain that we are in the same page though. The third charge, by sheer fact of the direction of the forces/ fields of spheres A & B, would have to be to right of the negative, since C is also negative, to cause A & B's directions to be inverse.

Answer 8

So C is on the x-axis at a distance greater than 1. I just don't understand how to find that distance... :/

Answer 9

correct correct.. why did you quit twiddla.? ll guide you through the drawings there.. come back