Finding q1 when q2 is in equilibrium with charges 10 cm and 20 cm apart

[jfusion]

Homework Statement

Charge q2 in the figure(Figure 1) is in static equilibrium. Assume that q = 4.4nC .

Figure:http://session.masteringphysics.com/myct/itemView?assignmentProblemID=31833513&offset=prev

what is q1 ( distance between q2 and q is 10com and distance between q1 and q2 is 20cm)

Homework Equations

F=k*q1*q2/(2d)^2 + k*q*q2/d^2 = 0

I then isolate for q1

The Attempt at a Solution

My answer is 1.7x10^-8 C which is wrong, I have converted all givens to Standard units

 

[vela]

We don't have access to the figure since we can't log into the publisher's site.

 

[jfusion]

Thanks for pointing that out, here's the image

 

[vela]

Maybe it's just a matter of rounding or sig figs.

 

[jfusion]

i don't believe so, do you come to the same conclusion?

 

[vela]

Yes, but when I round to two sig figs, I get a slightly different answer. Also, it could be that you didn't specify the correct sign of the charge.

 

[jfusion]

what do get as your final answer? and the charge would be + correct?

 

[jfusion]

it accepted 16nC thanks for the help