Calculating the electric potential

[ratnag93]

1. Two point charges 2.0cm apart have an electric potential energy -180 microjoules. The total charge is 30 nanocoulombs. What are the two charges?
Givens: change in postition = 0.02m , Q = 30nC = 3.0e-8C, V = -180 microjoules = 1.8e-4

Homework Equations

F = kq₁q₂/r^2
E = kq/r^2

The Attempt at a Solution

E1 = (9.00e5) (3.0e-8C)/(0.02m^2)...?

 

[thebigstar25]

the question is asking "What are the two charges?", so if we say that one of them has a charge "a" and the other a charge "b" .. then you are asked to find what is "a" and what is "b" ..

you are give r=2cm, electric potential= -180 microjoules, and a+b=30 nanocoulombs ..

hint: you are asked to find two unknows, so you will need two equations.. one of them is given as a+b=30 .. find another equation from the given quantities ..