# Homework Help: Point charges acceleration

1. Sep 12, 2010

### pimster987

Q1. If two point charges have equal mass and and charg are released on a frictionless table, each has an initial acceleration (Ao). if instead you keep one fixed and release the other one, what will be its initial acceleration?Ao,2Ao or Ao/2?

Q2. A point charge of mass (m) and charge (q) and another point charge of mass (m) but charge (2q) are released on a frictionless table. If the charge (q) has an initial acceleration (Ao), what will be the acceleration of (2q)?Ao, 2Ao, 4Ao,Ao/2, or Ao/4?

2. Sep 12, 2010

### diazona

Show us what you've tried and what you know that might be relevant to the problem.

3. Sep 12, 2010

### pimster987

Q1 Since both charges are the same they will repel one another. So I was comparing this problem to a ping pong ball problem I had in Physics I, when the force of the wall equals the force of the ball thrown. Wouldn't the acceleration just be Ao?

Q2 Since F=ma the mass is proportional to the acceleration therefore the acceleration should be 2Ao.

4. Sep 12, 2010

### diazona

1. I believe you're correct

2. Look at that equation carefully: the mass is not proportional to the acceleration.

5. Sep 13, 2010

### pimster987

They are inversely proportional so the acceleration should be Ao/2?

6. Sep 13, 2010

### diazona

You're right that in F=ma, the mass and acceleration are inversely proportional. But what are the masses of the two particles?

7. Oct 10, 2012