
#1
Feb1913, 09:40 PM

P: 20

1. The problem statement, all variables and given/known data
Three charges, each of magnitude 2 nC, are at separate corners of a square of edge length 1 cm. The two charges at opposite corners are positive, and the other charge is negative. Find the force exerted by these charges on a fourth charge q = +3 nC at the remaining (upper right) corner. (Assume the +x axis is directed to the right and the +y axis is directed upward.) 2. Relevant equations k = (8.988*10^9 N*m^2/C^2) 3. The attempt at a solution Drew a diagram of the problem such that F4 = F1,4 + F2,4 + F 3,4. F1,4 = (k*q1*q4)/(r(1,4)^2)j F1,4 = (8.988*10^9 N*m^2/C^2)(2.00*10^9)*((2.00*10^9)/(0.01m)^2) = 3.595 * 10^4 j F2,4 = same F3,4 = (k*q1*q2)/(r(2,4)^2)*r(3,4) r(3,4) = r(3,1) + r(1,4) = (0.01m)i + (0.01m)j r(3,4) = (0.01m)i+(0.01m)j/(sqrt(0.01m^2+0.01m^2)) = 0.14i + 0.14j F3,4 = (8.988*10^9) (2.00*10^9)(2.00*10^9)/(0.01sqrt(2)^2)*(0.14i+0.14j) = 2.52 * 10 ^ 5 (3.595 * 10^4) i  (2.52*10^5) i = 3.34*10^4i < Wrong :( (3.595 * 10^4) j  (2.52*10^5) j = 3.34*10^4j < Wrong :( Any suggestions?? I think that somewhere in computing F3,4 I put in an incorrect number. Thanks! 



#2
Feb1913, 10:11 PM

HW Helper
Thanks ∞
PF Gold
P: 4,481





#3
Feb1913, 10:30 PM

P: 20

Whoa, got .707 now, thanks. So then is everything else correct?




#4
Feb1913, 11:18 PM

HW Helper
Thanks ∞
PF Gold
P: 4,481

Three Point Charges, find the electric force exerted 


Register to reply 
Related Discussions  
Finding r using point charges and work done by an electric force  Introductory Physics Homework  2  
electric force due to point charges  Introductory Physics Homework  0  
Force exerted by two charges  Introductory Physics Homework  2  
Electric force between two point charges  Introductory Physics Homework  2  
Net force exerted by two charges on a 3rd charge  Introductory Physics Homework  1 