Calculating Potential Energy of Three Point Charges

disque · Sep 6, 2009

Homework Statement

Three point charges Q1 = 2.9 mu or micro C, Q2 = 4.9 mu or micro C and Q3 = 3.9 mu or micro C, are arranged as shown.

PE=k(q1q2/r+q1q3/r+q2q3/r)
k=8.99e9

By using that equation I plugged in the lengths and changed the 2.9 to micro coulombs.

Redbelly98 · Sep 6, 2009

disque said:

Homework Equations

PE=k(q1q2/r+q1q3/r+q2q3/r)
k=8.99e9

The Attempt at a Solution

By using that equation I plugged in the lengths...

Sounds like you have the right idea. You realize that "r" is different for each pair of charges, right?

... and changed the 2.9 to micro coulombs.

I'm not sure what that means. Just use 2.9e-6 C, etc., for the charge values.

disque · Sep 7, 2009

yea i got it, i had a negative sign and it was positive. not really sure why but thanks for your help