A charge of #-2 C# is at #(-2 , 1 )# and a charge of #-1 C# is at #(1 ,-3) #. If both coordinates are in meters, what is the force between the charges?
The force between the charges is given by Coulomb's Law,
The first step is to find the distance between the two charges:
So the points are
Now use Coloumb's Law. The constant k has the value
This is quite a large force, but it's unsurprising because a coulomb is quite a large amount of electric charge, and because the constant in Coulumb's Law is so large (electrostatic forces are much stronger than gravitational forces, for example).