Hi guys I have 3 question the first one I want to check if my answer is correct or not but the two other question I don't know how to approach them thanks.(adsbygoogle = window.adsbygoogle || []).push({});

1)The 500 gram mass carries a charge of –7 x 10-8 C. If the coefficient of friction between the mass and the surface is 0.20, and an electric field of magnitude 3 x 107 N/C is horizontal and directed to the right, which is being treated as the positive x-direction. What is the acceleration of the mass?

Ff = force of friction;

Ff = 0.2 * (500 * 10^-3) = 10^-1N;

Fe = qE;

Fe = (-7 * 10^-8) * (3 * 10^7) = -2.1N;

Fnet = -2.1 - 10^-1 = -2.2N;

F = ma;

-2.2 / (500 * 10^-3) = a; --> a = -4.4 m/s^2;

I can't find that answer in the multiple question,so did I do something wrong here?

2)What is the magnitude and direction of the electric field generated by a 13 μC charge in a point 8.90 cm away from the charge?

How can I know the electric field generated even though I am not given a point charge ? Thats what confusing me in this question.

3)A +2 μC charge is at the origin. A +5 μC charge is on the x-axis at +1 m. At what point between the charges is the electric field zero?

I first calculated the electric field Electric field from

F = kQ1 * Q2 / d^2.

I got electric field of the 5μC = (9 * 10^4) / 5 and the electric field of the

2μC = (9 * 10^4) /2.

I don't know how to proceed from here to get the distance of the zero electric field.

This is not a homework or anything I am solving some electrostatic problems on my own.

Thanks for the help in advance.

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# Homework Help: Electrostatic problems help

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