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Question with Charges and Proton?

A 4 nC charge is at the origin and a -5 nC charge is at x = 5 cm.

At what x-coordinate could you place a proton so that it would experience no net force?

1 Answer

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  • Anonymous
    1 decade ago
    Favorite Answer

    You have to find where

    4 / d^2 ( force from the 4 nC charge ) = 5 / (d + 5 )^2 ( force form the 5 nC charge )

    4 ( d^2 + 10d + 25 ) = 5d^2

    d^2 – 40 d – 100 = 0

    d = 42.4 cm

    There is another solution but this lies between the two charges and there the forces cannot add to zero. Only on the left... at negative x, can the forces add to zero. ( This is where the Physics understanding comes in.... the rest is just maths. )

    The coordinate you want is – 42.2 cm

    Source(s): Old teacher
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