# Homework Help: Electric Forces in a Triangle (math check?)

1. Feb 11, 2012

### CrzyMunky

Hi Guys I've tried to do this problem but the answers are not being accepted is the math wrong? or did i forget a concept? Thanks for taking a look

The triangle is set by Q1 on the top of the triangle Q2 on the bottom left and Q3 on the bottom right

Calculate the magnitude of the net force on each due to the other two. Three charged particles are placed at the corners of an equilateral triangle of side 1.20 (see the figure ). The charges are Q1= 7.0 , Q2= -8.6 , and Q3= -5.4 .

F(e)= k (Q1*Q2)/ r^2

F(12) =(8.98e9*7e-6*8.6e-6)/ (1.2)^2 F(23) = 8.98e9*8.6e-6*5.4e-6/ (1.2)^2

F(31) =(8.98e9*5.4e-6*7e-6) / (1.2)^2

F(12) = .3754N
F(23) = .2896N
F(31) = .2357N

Fx1 = -Cos(60)(.3754)+Cos(60)(.2357)= -.069
Fy1 = -Sin (60) (.3754)-Sin(60)(.2357)=-.121

F1= sqrt((-.069)^2+(-.121)^2)= .139

Fx2 = -Cos(60)(.3754)-.2896=-.1025
Fy2 = Sin(60)(.3754)=.3247

F2= sqrt((-.1025)^2+(.3247))=.340

Fx3 = Cos(60)(.2357)+.2896=.4075
Fy3 = Sin(60) (.2357)=.204

F3= sqrt((.4075)^2+(.204)^2)=.226
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