# Electrostatic force on a charge

1. Aug 26, 2009

### astro2cosmos

i was reading the book of Griffin - introduction to electrodynamics. it is written that the force of charge q on Q is not only depends on the distance b.w them but also the velocity & acceleration of charge q.then i think coloumb'law is incomplete at all. it must include some quantity for velocity or acceleration. ian't it right??????????
hope for this >>>>>>>>

2. Aug 26, 2009

### olgranpappy

Yes, "coloumb'law" is incomplete. This incompleteness is a topic within the field of electrodynamics (note the phrase *dynamics* as opposed to statics), an introduction to which is presumably given in the book you mentioned.

3. Aug 26, 2009

### clem

Yes. If you go further on in the book, you will get to the Lienard-Wiechert potentials which replace Coulomb's law for moving and accelerating charges.

4. Aug 26, 2009

### Staff: Mentor

The dependence of the force on the velocity of q is usually called "magnetism."

5. Aug 26, 2009

### astro2cosmos

yes it may right like it is something electromagnetic force b.w the particles, then why didn't coloumb mention it in his Law???????

6. Aug 27, 2009

### Staff: Mentor

Isn't Coulomb's Law confined to electrostatics? That might be why...

http://en.wikipedia.org/wiki/Coulomb's_law

No v or a in his equation that I can see...

7. Aug 27, 2009

### olgranpappy

The man's name is Coulomb not "coloumb". He studied electricity a long time ago... He didn't get *everything* exactly right but he got pretty close. Cut the man some slack. Geez.

8. Aug 27, 2009

### Staff: Mentor

Because at the time Coulomb did his work, the velocity-dependent force hadn't been discovered yet!

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