Calculating Force of Charges & Size to Double Magnitude - Homework Help

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The discussion revolves around calculating the force between two point charges of +1.4nC and +1.6nC, which are 40cm apart, using Coulomb's law. The user initially calculated the force as 1.25 x 10^7N but later questioned if it should be 10^-7N instead. For the second part of the problem, which involves determining the charge needed on a third conductor to double the force on the 1.4nC charge, the user is struggling to find the correct solution. Other participants suggest sharing the user's calculations for better guidance on the errors made. The thread emphasizes the importance of accurate calculations and understanding the application of Coulomb's law.
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Homework Statement


Hi
I need clarification on this problem. Calculate
a) the force between 2 charges of +1.4nC and +1.6nC on point conductors 40cm apart in air.
b)What size of charge on a third point conductor placed midway between the first two conductors would result in doubling of the magnitude of the force on the 1.4nC charge?



Homework Equations


Coulombs law= (Kq1q2)/r^2



The Attempt at a Solution


I obtained 1.25 x 10^7N for the first part. For the second part, I stated the new charge as q and the new distance as 20cm. Making the new charge the subject of my formula, i put in the new details. But my result is not correct.

Please any advise. Thanks
 
Last edited:
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aurao2003 said:
I obtained 1.25 x 10^7N for the first part.
Please any advise. Thanks

Shouldn't it be 10^-7 ?

and can't tell you the solution

if you can post your solution, i can tell you what you did wrong
 
cupid.callin said:
Shouldn't it be 10^-7 ?

and can't tell you the solution

if you can post your solution, i can tell you what you did wrong
Yeah! Thanks. Its -7
 

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