# Homework Help: Force of repulsion

1. Sep 12, 2016

### Deebu R

1. The problem statement, all variables and given/known data
two similar charged bodies are kept 5 cm apart in air. If the second body is shifted away from the first another 5 cm, there force of repulsion will be?

2. Relevant equations
Coulomb's law? F= k (q1q2)/r^2?

2. Sep 12, 2016

### Drakkith

Staff Emeritus
What do you think? What are your thoughts on this problem? What does Coulomb's law govern?

3. Sep 12, 2016

### Deebu R

force of attraction or repulsion is directly proportional to product of charges and inversely proportional to square of the distance between them. So....if the r is moved by another 5 cm r^2 also increases.
When r= 5 r^2 = 25
When r=10 then r^2 is 100
Since it is inversely proportional the force reduces by 1/4. True?

4. Sep 12, 2016

### Drakkith

Staff Emeritus
Yep! When you double the distance, you reduce the force to 1/4 of its original strength. If you triple the distance, the force is reduced to 1/9 the strength.

5. Sep 12, 2016

### Deebu R

I was not sure if my answer was correct or not. Now I know. Thank you for your time.