Electric Forces: Need Help Solving!

[BuBbLeS01]

Electric Forces...need help!

Homework Statement

Two small plastic spheres each have a mass of 2.85 g and a charge of -39 nC. They are placed 3.06 cm apart (center to center).

A. What is the magnitude of the electric force on each sphere?

B. By what factor is the electric force on a sphere larger than its weight?

Homework Equations

The Attempt at a Solution

A. K*q*q / r^2 = 0.0146 N
B. I thought I could just do 0.0146 N / (0.00285kg * 9.81 m/s^2) = 0.523...is that right?

 

[Shooting Star]

The concept is right.

 

[BuBbLeS01]

so what am I doing wrong??

 

[Shooting Star]

Are you? What? I haven't checked the numbers.