# Electric force charges homework

1. Sep 20, 2013

### danish1991

1. A student is performing an experiment with two identical small metal balls, A and B. Initially, Ball A contains 6.0-uC net charge with unknown sign and Ball B is neutral. The student brings them in contact and then separated them by 20cm. Both of the balls are remained isolated. Is the electric force between A and B attractive, repulsive or zero?

2. Sep 20, 2013

### tiny-tim

hi danish1991! welcome to pf!

what happens to the charge when the metal balls are in contact?

tell us what you think, and why, and then we'll comment!

3. Sep 20, 2013

### danish1991

Okay, thanks for replying! Its either between repulsive or zero. It cannot be attractive since both charges aren't opposite. I know its repulsive as the correct answer but wouldn't it be zero since ball b is neutral charged and ball a is positive because for attractive both charges gotta be opposite to each other, repulsive they gotta be same since its positive and zero how would it be repulsive?

4. Sep 20, 2013

### danish1991

Okay, thanks for replying! Its either between repulsive or zero. It cannot be attractive since both charges aren't opposite. I know its repulsive as the correct answer but wouldn't it be zero since ball b is neutral charged and ball a is positive because for attractive both charges gotta be opposite to each other, repulsive they gotta be same since its positive and zero how would it be repulsive?

5. Sep 21, 2013

### tiny-tim

hi danish1991!

(just got up :zzz:)