Static Electricity and particles

AI Thread Summary
The discussion revolves around calculating the net force on three charged particles: +70 µC, +48 µC, and -80 µC, arranged in a line with specific distances. The user initially applies the formula F=kq1q2/d² but struggles with the correct application, particularly in considering the signs of the forces and their vector nature. They are advised to draw a diagram, analyze one charge at a time, and carefully account for the distances and directions of the forces. Despite performing calculations, the user receives feedback that their final answer is incorrect, indicating a misunderstanding in the superposition of forces. The thread emphasizes the importance of correctly applying vector addition and considering the effects of charge signs on force direction.
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Homework Statement



Particles of charge +70, +48, and -80 \muC are placed in a line, in the previous order. The center one is .35 m from each of the others. Calculate the net force on each charge due to the other two.

Homework Equations



F=kq1q2/ d2


The Attempt at a Solution



I found the force between each but according to my teacher I am not doing this correctly could someone please tell me how i should go about doing this problem.
 
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Draw a diagram. Consider one charge at a time.

The ones on the end will be .35 and .7 distant from the other 2 respectively.

Be careful with the signs. Be careful with the units.

Be careful that you have taken care to note the direction of the force in each equation. (+,-) attracts and same sign repels.

Since forces are vectors then you must take that into account when you add them by superposition.
 
I thought that's what I was doing but after trying again i got the same wrong answer, I'm so confused about wht i should do with this problem!
 
Show your calculation then for the middle charge.
 
LowlyPion said:
Show your calculation then for the middle charge.

F1= (9x109)(70 x 10-6)(48x10-6)/ .352

this equals: 246.86

F3= (9x109)(-80 x 10-6)(48x10-6)/ .352


this equals: -282.1

Then i did
(246.862)+ (-282.12)= Q2

Q= 374C

but according to my teacher this is wrong... can you tell me what it is that I am doing wrong?
 

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