Coulomb's Law in 3D: Find Electric Force & Field

[Sofia Matthews]

Homework Statement

q1= 5 x 10^-6C position (1;2,-1)
q2= -3 x 10^-6 C position (-2,1,3)

a) what is the electric force caused by q2 on q1? (vector notation)
b) what is the electric field at (0,0,0)

Homework Equations

F = kq1q2/r^2
E= F/q

The Attempt at a Solution

I really don't know how to start this problem. Since this problem is in 3D, I don't know how to find the z coordinate of the electric force.

What I initially did was to find the electric force with Coulomb's law, but it gives me a number and not components. I tried to play with Pythagoras's theorem, but didn't figure anything out. [/B]

 

[cnh1995]

Welcome to PF!

I really don't know how to start this problem.

You need to provide an attempt. It is mandatory while posting in the homework help section.

 

[haruspex]

I don't know how to find the z coordinate of the electric force.

In terms of the positions P and Q of two charges, what is the line of action of the force between them?