- #1
Clara Chung
- 304
- 14
Homework Statement
PQRS is a square. Three point charges -Q, +Q and -3Q are fixed at P, Q and S respectively as shown.
A point charge q is then placed at R and it experiences a net electric force towards S. Which of the following is equal to q?
photo :
http://s613.photobucket.com/user/Yan_Wa_Chung/media/01_zps421rebzc.png.html
Homework Equations
F=kq1q2/r^2
The Attempt at a Solution
in any kind of calculation, Q and q are canceled out and undetermined ,ie : (k1) (q) (Q) / (r1)^2 = (k2) (q) (Q) / (r2)^2, (turn force PR to vertical and horizontal component cancel the vertical component with force QR) . I have no idea on the question or maybe the question itself has mistakes ?The right answer is q=1/9 Q.