Find the force acting on the charge at the origin

[pat666]

Homework Statement

Three charges are fixed in the x-y plane as follows: 1.6nC at the origin (0, 0); 2.6nC at (0.55 , 0); –2.1 nC at (0, 1.15 ).

Find the force acting on the charge at the origin.
Express your answers using two significant figures. Enter the x and y components of the force separated by a comma.

Homework Equations

F=kQQ/r^2

The Attempt at a Solution

Fx=(2.6E-9*1.6E-9*9E-9)/1.15^2=1.24*10^-25N
Fy=(2.1E-9*1.6E-9*9E-9)/0.55^2=2.29*10^-26N
This is wrong but i can't see why??

 

[rl.bhat]

For Fx r is 0.55 m not 1.15 m. And k = 9*10^9

 

[pat666]

thanks rl.bhat I have the right answers now. I just don't know which one would be negative, I am thinking Fy? thanks