Centripetal Forces Physics l

Question

1. We know that two positive charges repel each other.
a) Determine the force between two charges which are both +1C and separated by 1m.


b) Why do we normally measure charge in µC instead of Coulombs?

Answer 1

(a)

 

Use Coulomb's law.

 

F = kq₁q₂ /r₁₂² = (9.0 x 10⁹ Nm²/C²)(1C)²/(1m)² N = 9.0 x 10⁹ N

 

(b)

 

We normally use μC (10^-6 C) or even nC (10^-9 C) because 1C is an extremely large amount of charge, and hence not realistic to work with in everyday use.