Coulomb's law Definition and 403 Threads

Homework Statement A charge of 6.00 x 10-9C and a charge of -3.00 x 10-9C are separated by a distance of 60.0 cm. Find the position at which a third charge, of 12.0 x 10-9C, can be placed so that the net electrostatic force on it is zero. Homework Equations Coulomb's Law The...

Homework Statement Three charges are arranged as shown in the picture I attached. Find the magnitude and direction of the electrostatic force on the charge at the origin.Homework Equations I know that Coulomb's Law must be applied.The Attempt at a Solution I've drawn a force diagram with FCB...

I know that for electric field you always have to break E up into the x and y components for each charge---do you have to do the same thing when finding electric force using Coulombs law? I get the correct answer when i do NOT break F up into components (ie when finding F between 2 charges with...

New to PF. How is the "original" form of coulomb's law F=kQ1Q2/D^2 derived into the modified chemistry form used to predict the energy released when bonds form (or the inverse), E=kQ1Q2/r? Please describe your mathematical steps. Feel free to just post links explaining this. I've searched...

Homework Statement I am a maths teacher retraining in physics, haven't received my textbook yet but attempting the course work, I have the answer to this question and the mathematic skills to solve it, but the notes don't give any worked examples so I have no idea how to go from the law to the...

Homework Statement The sum of two point charges is 6µC. They attract each other with a force of 0.9 N, when kept 40 cm apart in vacuum. Calculate the charges. Homework Equations The Attempt at a Solution q1+(-q2) = 6x10-6 q1-q2=6x10-6...I q1=6x10-6+q2 According to Coulomb's law...

Hi everyone, I got a little question. Let's say we have 3 point charges on a line, for example on the x axis. 1----2----3 something like this. If I want to calculate the Force on point charge one, why am I allowed to just add the forces 12 and 13. I saw it in a book and was confused...

Homework Statement The charge is distributed with uniform surface density σ on the disk of radius R. Find the potential at the axis of the disk. Homework Equations Coulomb's law and the definition of a electric potential at point x The Attempt at a Solution I have a solution in...

I can show that Coulomb's Law + superposition implies \nabla \cdot \mathcal {E} = \frac{\rho}{\epsilon_0} and \nabla \times \mathcal{E} = \mathbf{0}. I want to go the other way and derive Coulomb's law and superposition from the vector identities. I know that Gauss' Law implies Coulomb's law if...

Homework Statement A charge q1 = 5uC is placed at (x,y,z):(1,2,-1). A charge q2 = -2uC is placed at (x2,y2,z2):(-2,1,3). Determine the electric force (vectorized form) exerted on q1. Homework Equations F12= kQ1Q2 / r2 The Attempt at a Solution At first I tried finding the distance between...

Homework Statement Two electrostatic point charges of +60 microCoulombs and +50 microCoulombs exert a repulsive force on each other of 175 N. What is the distance between the two charges? Homework Equations Fe=Kc (q1*q2/r^2) The Attempt at a Solution I know I need to rearrange...

I didn't use latex because for some reason, a term with the 10 to the power of -# isn't working properly: 1.0*10^-1 Homework Statement Two identical objects have charges +6.0 microcoulombs and -2.0 microcoulombs, respectively. When placed a distance "d" apart, their force of attraction is...

Homework Statement Strictly speaking, the description of Coulomb's law given on the previous page (written below this paragraph) is meant to apply to point charges. However, just as Newton was able to develop the mathematics(calculus) that proved the mass of any spherical object can be...

Homework Statement In our physics lab about the Coulomb's law we had an Van de Graaff Generator (VdGG) to produce a charge and we had a sphere covered with foil (a conductor) which was hang up next to the VdGG. When the VdGG produced charged the sphere was attracted to it and finally touched...

This isn't homework, just a bit of extra study that is annoying me. Can't really seem to get my head around this bit. If you have a worked equation of Coulomb's law and all known variables; Force, Distance between two objects and the charge in Coulomb's, how do you represent this in a graph...

Homework Statement Two point charges are fixed on the y axis: a negative point charge q1 = -28 µC at y1 = +0.25 m and a positive point charge q2 at y2 = +0.38 m. A third point charge q = +8.5 µC is fixed at the origin. The net electrostatic force exerted on the charge q by the other two...

1. The problem statement, all variables given/known data A particle of charge 6 µC is held fixed while another particle of charge 8 µC is released from rest at a distance of 1.4 m from the first particle. If the mass of the second particle is 3x10-6 kg, what is its speed when it is very far...

Well, I am raging over my homework and not even going to turn it in because I can't complete enough of it. I really just need to figure this problem out so I don't feel as bad about it. I know this shouldn't be as hard as I am making it, but all examples only have answers containing a...

Homework Statement "Three identical charges, each with charge 'Q' and a mass 'm', are arranged on the corners of an equilateral triangle of side length 'L'. The spheres are released simultaneously. What is the speed of each charge when they are very far apart? Homework Equations F =...

Homework Statement What is Coulomb's law? Describe what needs to exist in order for the Coulomb based force to exist. What does this force act on? Where does it act? Homework Equations The Attempt at a Solution Coulomb’s law states that the electrical force between two charged...

Homework Statement In lab, there was a string with a charged ball, and another charged ball moved closer to it. The ball's repelled and we had all sorts of data to calculate. I did a graph of the D vs 1/R^2 and the points fell almost right on. However, towards the end of that line, the...

Homework Statement Corrected Angle, theta, vs Distance, r, demonstrate or relate to Coulomb's Law how? Homework Equations Coulomb's Law The Attempt at a Solution As the distance increases, the force decreases by a factor of 4 because "r" is squared in Coulomb's law. Homework...

Homework Statement Three identical point charges, each of magnitude q, are located on the vertices of an isosceles triangle with its altitude oriented vertically. The altitude of the triangle is 4.00cm and the base is 6.00cm long. The resultant electrical force on the charge located at the...

Homework Statement http://img547.imageshack.us/img547/7932/14207376.png [PLAIN]http://img684.imageshack.us/img684/719/75458442.png [PLAIN][PLAIN]http://img88.imageshack.us/img88/4883/55224430.png Assume q_{1}=q_{2}=q_{3} and that all charges are positive. The Attempt at a...

Homework Statement Suppose that resting on your non-conducting desktop is a tiny piece of paper(m=0.08g) that carries a charge of +4 x 10-10C. You comb your hair and then slowly lower your comb until when it is 3 cm away from the paper, the paper jumps up to the comb. a) Give an approximate...

Homework Statement Of the charge Q initially on a tiny sphere a portion q is transferred to a second nearby sphere. Both spheres can be treated as particles. For what value of q/Q will the electrostatic force between the two spheres be maximized? Homework Equations Coulomb's Law We...

Homework Statement Of the charge 'Q' initially on a tiny sphere, a portion q is to be transferred to a second, nearby sphere. Both spheres can be treated as particles. For what value of q/Q will the electrostatic force between the two spheres be maximized? The Attempt at a Solution The...

Homework Statement Suppose the the Earth were made only of protons, but had the same surface size and mass it presently has. What would be the acceleration of an electron released at the surface? Disregard gravitation force. Homework Equations F=(keq1q2)/r2 The Attempt at a Solution...

I don't really know how to solve this problem. I only know how to calculate the net force on B, not A... here is the problem: sphere A is located at the origin and has a charge of +2.0x10^-6 C. Sphere B is located at +.6m on the x-axis and has a charge of -3.6x10^-6 C. Sphere C is located...

Homework Statement When I try working out the example below from PlanetPhysics, I wind up with 2PI rather than 4PI in my answer. Should I be considering my result valid for only a hemisphere and double it for a sphere--or am I just making a mistake in my math? "As an example of the...

This is more of a general question than a homework problem. We haven't gotten too far into e&m so maybe there is a different use for this later on that I just haven't seen yet. Even skipping 7-8 chapters ahead, it is still used in the same way. What is the point of using...

Coulombs law in SI system is given by from where does the factor 4\pi come in.

Homework Statement Two point charges are fixed on the y axis: a negative point charge q1 = -24 µC at y1 = +0.20 m and a positive point charge q2 at y2 = +0.37 m. A third point charge q = +9.0 µC is fixed at the origin. The net electrostatic force exerted on the charge q by the other two...

Homework Statement Two positive charges +Q are affixed rigidly to the x-axis one at x = -d and the other at x = +d. A third charge +q of mass mwhich is constrained to move only in the x-axis is displaced from th eorigin by a small distance s << d and then released from rest. Show that q+...

Homework Statement distance between two electrical charges q1=10nC, q2=16nC is 7mm , what force will act at third charge q3=2nC, placed between the first two charges 3mm far from the smaler charge and 4 mm far from the larger charge.Homework Equations Fc=k*|q1||q2|/r2 The Attempt at a Solution...

Homework Statement Two negatively charged objects repel each other with a measured force of 6.3 N when they are 0.5 cm apart. If the excess charge on one of the objects is caused by 8.3 x 10^22 extra electrons, use Coulomb's Law to calculate the number of excess electrons on the second object...

I thought this would be a basic physics problem, but I'm not getting the right answer, here's the problem: There are two identical small metal spheres with charges 27.5 μC and −19.119 μC. The distance between them is 8 cm. The spheres are placed in contact then set at their original...

Homework Statement Two identical particles, each having a charge of +q are fixed in space and separated by a distance d. A third particle with charge -Q is free to move and lies initially at rest on the perpendicular bisector of the two fixed charges a distance x from the midpoint between the...

F=\frac{q1q2}{4\pi\epsilon_{0}} If epsilon 0 was defined as the proportionality constant for this equation, why was 4 pi not included in Eo? Why does there have to be a 4pi in the equation, instead of just having Eo equal its current value times 4pi?

Homework Statement Three charges lie along the x-axis. The positive charge q1 = 10.0 x 10^-6 C is at x = 1.00 m, and the negative charge q2 = -2.00 x 10^-6 C is at the origin. Where must a positive charge q3 be placed on the x-axis so that the resultant force on it is zero? Homework...

I was noodling about with 4-vectors and Maxwell's Equations when I took it upon myself to figure out how to write the field of a point charge in terms of 4-vectors, since I'd never seen it before (if anyone knows a book that has this I'd be happy to see it). It's actually relatively simple...

Homework Statement An electron is separated from a potassium nucleus (charge 19e) by a distance of 5.2 X 10-10m. what is the electric force between these particles? (e = 1.60 X 10-19C, Kc= 8.99 X 109 N*m2/C2)Homework Equations Felectric= Kc[(q1)(q2)/r2] The Attempt at a Solution Felectric=...

I've been working on this problem for a while but i am getting confused on vector directions. Four point charges are arranged in a square with sides of 0.38m. Find the magnitude and direction of the force at each corner of the square. Point 1=3nC Point 2= 19nC Point 3=...

Homework Statement Three charged particles are placed at each of three corners of an equilateral triangle whose sides are of length 3.5 cm. Two of the particles have a negative charge: q_1 = -8.0 nC and q_2 = -16.0 nC. The remaining particle has a positive charge, q_3 = 8.0 nC. Assume that...

Homework Statement 1. A positively charged object with a charge of +85 nC is being used to balance the downward force of gravity on a 1.8-gram balloon which has a charge of -63 nC. How high above the balloon must the object be held in order to balance the balloon? (NOTE: 1 nC = 1 x 10^-9 C)...

so my book has a point charge q inside an arbitrary surface S and at a point P on the surface S, the electric field is E = q/4(π)(ε0)(r2). so the flux through S is then dΦ = E * dS = q/4(π)(ε0)(r2) * dS = q/4(π)(ε0) * dScosθ /(r2) = q/4(π)(ε0) * dΩ. then my book takes the integral of both sides...

Homework Statement Homework Equations E = (q(R-R')) / (4*pi*epsilon*|R-R'|^3) The Attempt at a Solution Ignore the MATLAB part of the problem .. i can do that easily. I just need a head start ... so should i first calculate the E between the specified set of points and each...

Homework Statement two pith balls are suspended on a wooden dowel and have the same origin point. the two balls are push away from each other and are equally negatively charge. the string have the length L and the two strings form angle (theta). knowing Fg= Gm1m2/r^2 Fe= kq1q2/r^2...

Any answers would be great, thanks! Homework Statement 1. A charge Q is uniformly spread along the x-axis from x=0 to x=l. Find the electric potential function at points on the x-axis for x>l. 2. An electron moves from one point to another where the second point has a larger value of the...

Why the 4π in Coulomb's Law, SI version? The CGS version does well without it...:confused: \mbox{thanks in advance!}