# Homework Help: Two 1.0-g beads are charged .?

1. Oct 2, 2007

### mikebc

Two 1.0-g beads are charged .....????

Hi, I have never posted before but have seen great help given to people who are confused. I would really appreciate help on this question if possible.

"Two 1.0-g beads are charged equally and placed 5.0 cm apart. When released,
they begin to accelerate at 150 m/s2. What is the magnitude of the charge on each

I am pretty sure I know how to do this question with the equation; (q2=Fr2/k), but I am not too sure if I use gravity or acceleration to find the force. F=ma. I think I would use acceleration since it is given in the question.

Any help would be greatly appreciated. Thanks.

2. Oct 2, 2007

### Staff: Mentor

Assume that the only force acting is electrostatic attraction (ignore gravity, friction, etc.). So just use Newton's 2nd law to figure out the force and then apply Coulomb's law, just as you stated.

3. Oct 2, 2007

### mikebc

Thank you very much for your help...and quick response! I understand.