How Does Coulomb's Law Apply When Socks Repel in a Dryer?

[lalablu3]

Homework Statement

You remove two socks from a hot dryer and find that they repel with force of 0.002 N when they’re 1 cm apart. If they have equal charges, and you separate the socks until they’re 5 cm apart, what force will each sock exert on the other? Round the answer to 3 significant digits.

Homework Equations

F=8.9*10^9(q1)(q2) / r^2

The Attempt at a Solution

Ive been working on this for over an hour and am frieking out! First I try to solve for the two charges, using .1 (1cm-converted to meter). I know that once I get this, I can use it to change .1 to .5 and solve for F. Problem is I have been having trouble solving for Q! which leaves me stuck in the begining.

Please please help, I've got a midterm in the morning.

 

[Abraham]

F=kq1q2/r^2

at .01m, F = .002
Solve for q^2, since q1 = q2
q^2= (0.002)(.01^2) / (8.9e+9)
= 2.25e-17 C
so q1 or q2 equals the square root of q^2:
(2.25e-17)^0.5 = 4.74e-9 C

Then, use these values to solve if r = .05 (just plug them back into the equation)

I hope this helped