# Finding the magnitude of the positive charge

1. Sep 4, 2011

### fal01

Two conducting spheres have identical radii. Initially they have charges of opposite sign and unequal magnitudes with the magnitude of the positive charge larger than the magnitude of the negative charge. They attract each other with a force of 0.231 N when separated by 0.5 m.

The spheres are suddenly connected by a thin
conducting wire, which is then removed.

Now the spheres repel each other with a forceof 0.022 N
What is the magnitude of the positive
charge?
Answer in units of C

so I know the equation F=k(Q1Q20/r^2)

Initial: .231N=(8.98*10^9)Q1*Q2/0.5^2

then I assume the final will look something like this...

.022N=(8.98*10^9)Q1*Q2/r^2

I am not sure how use the initial information with the final information in order to find the magnitude of the positive charge

Last edited: Sep 4, 2011