# Coulombs Law & Electric Charges

#### ali13

1. Homework Statement
Two negative electric charges, (Charge A on the left, and Charge B on the right) each with a charge of 3.0 x 10-5 Coulombs are fixed at a distance of 2.9 meters from each other. Find the electric force of charge A on charge B. (Don't forget, if the force points to the left, then the force is negative).

2. Homework Equations
I=Q/T
F=K(Qq)/r^2

3. The Attempt at a Solution
(9*10^9)*(-3.0*10^-5)*(3.0*10^-5)/2.9^2

=-.963

i feel comfortable with that, but then i'm stumped when it asks, "find the electric force of Charge B on Charge A in Newtons." and finally, "Suppose Charge B has a mass of 0.06 kilograms, and is now allowed to move freely. Find the acceleration of Charge B."

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#### Tom Mattson

Staff Emeritus
Science Advisor
Gold Member
but then i'm stumped when it asks, "find the electric force of Charge B on Charge A in Newtons."
The magnitude of the force that B exerts on A is the same as the magnitude of the force that A exerts on B.

and finally, "Suppose Charge B has a mass of 0.06 kilograms, and is now allowed to move freely. Find the acceleration of Charge B."
If you know the force exerted on B and the mass of B, then Mr. Newton gives you the acceleration of B.

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