Electric Forces

1. Oct 18, 2004

punjabi_monster

Two point charged objects produce an electric force on each other of 6.20 * 10^-2 N. What is the electric force if the distance between increases three times?

I understand that this formula can be used, Fe=(kq1q2)/R^2, but how can you determine K and R from this formula. Any help would be appreciated.

2. Oct 18, 2004

Tide

It's simple ratios and proportions. Write out the two forces for each case then divide one equation by the other - the K will cancel out and so will the R if you use the information provided.