Conceptual physics question?

Question

I'm not certain of the answer, but...:
There is a negatively charged object lying on the ground. A neutral metal ball rolls toward this object and stops (i.e. due to friction) some distance away from the ball and does not touch it (implies induction, separation of charge.) A second neutral metal ball then hits the first ball on the back of the ball, i.e. on the side away from the negatively charged object, and transfers its momentum onto the middle ball, and stops. The middle ball then rolls toward the negatively charged object and stops (due once again to friction).
What is the net charge (+ or -?) at the end of all of this for each of the two metal balls?

My reasoning is: b/c of separation of charges, there are electrons concentrated at the back end of the first ball. Then, by conduction, electrons flow into the second neutrally-charged ball. The second ball thus acquires a negative charge, and the first a positive charge. But it seems mroe complicated than that...

I guess the main question here is between two choices: is it the more obvious (+ and - charge) answer, or is it that charge does not get transferred? I lean toward the latter, b/c it seems that even w/out grounding, they don't have net charges, so even with a separation of charge, electrons may not get transferred. Conduction requires that the neutral metal object be in contact w/ a charged object. Also, grounding would be another reason. So I guess that makes sense. Anyone want to argue for the opposite view?

Also, I understand that conduction requires a charged object to be in contact, but if there is a charged object on the other side, and the negatively charged object is pulling on the positive charges with an actual force (repelling negative charges also w/ a force), isn't it true that the electrons can't redistribute themselves evenly along the two balls?

Answer 1

To make this scenario meaningful, let's say the balls are on a perfect insulator rather than just on the ground. You have the right idea. Because of the repulsive force from the negative charge, electrons on the first ball will tend to migrate away from that negative charge. When the second ball makes contact, the pair effectively just makes a bigger ball. Indeed, after the contact, the second ball will contain more electrons than the first. When they separate, that charge disparity remains. The first ball will have a net positive charge, and the second will have a net negative charge. See the reference for a phenomenon something like this on an atomic/molecular level.

Answer 2

Here is my answer, I am not sure if this is the exact solution though. At the first case when the ball stops infront of the charged object the charges redistribute such that one side (nearer to the charged object) of it has positive and the other side negative as to make total charge zero. You should remember that the total charge on this ball is zero though. Also these are bound charges which means that they cannot be transferred even if you ground one side of it.



So effectively the second ball is hitting a ball which has bound charges and i dont think the charge would be transferred to it.
I might very well be wrong and I would keep on eye for answers to this question.


Please check the concepts of bound charges to get an answer for this

Answer 3

I just had this question on a test; your reasoning is exactly what I put down. But since it was supposed to be hard question, I'm not so sure. In the first ball scenario, the ball gets polarized, and there is a slight attractive force (overcome by friction, no doubt). In the second frame, just at the point of contact, they're both neutral, so I'm not sure if conduction happens or the charges spread themselves evenly throughout the two surfaces. But b/c there is that force due to the negative charge, it seems reasonable. idk, probably I'll get partial credit at least.

Answer 4

Conceptual physics may basically concentration on the reasoning and techniques in the back of the technology of physics. So in conceptual physics, you may be informed about friction, forces, thermodynamics, ect. in spite of the undeniable fact that, you'll not ask to finish any calculations. that's what you do in regularly occurring physics. you take advantage of the techniques and use math to scrub up complications. So case in point, you may study about stress, and as a difficulty you may favor to make certain what the acceleration an merchandise of a particular mass should be to make certain that a particular stress to be produced(that's an more beneficial accessible problem). also, there are diverse levels of physics. you may take physics that calls for in undemanding words an information of Algebra, or you'll get a touch more beneficial progressed and take Physics for technology and Engineering that's calculus depending.

Answer 5

The net charge for the metal balls would be neutral due to the fact that neither of the metal balls would hold a charge.

Any conductor that is grounded has it's charge dissipated, doesn't it?
.

Answer 6

My impression is that you have it right.