Coulomb's law Definition and 396 Threads

Homework Statement What is the magnitude of the force on an electron at a distance of 1.79 Angstrom from the radium nucleus? Homework Equations Coulomb's Law: F = \frac{1}{4 \pi \epsilon_0} \ \frac{q_1 q_2}{r^2} The Attempt at a Solution For this problem, I...

A system consists of two positive point charges, q_1 and q_2 > q_1. The total charge of the system is 64.0 \mu C, and elec each charge experiences antrostatic force of magnitude 76.0 N when the separation between them is 0.270 {\rm m}. Im having a little trouble determining q1, it must be...

1. Homework Statement Two point charges q1 = -5.60 nC, and q2 = -14.0 nC are separated by 25.0 cm (see figure below). http://www.webassign.net/yf12/21-p-031-alt.gif (a) Find the net electric field these charges produce at point A magnitude 10360 N/C direction is to the right (b)...

Homework Statement Two point charges q1 = -5.60 nC, and q2 = -14.0 nC are separated by 25.0 cm (see figure below). http://www.webassign.net/yf12/21-p-031-alt.gif (a) Find the net electric field these charges produce at point A magnitude 10360 N/C direction is to the right (b)...

Homework Statement A ring-shaped conductor with radius a = 2.20 cm has a total positive charge Q = +0.145 nC uniformly distributed around it, as shown in the figure below. The center of the ring is at the origin of coordinates O. (a) What is the electric field (magnitude and direction) at...

Homework Statement Two charges, one of 2.50 micro coulomb, and the other of -3.50 micro coulomb, are placed on the x-axis, one at the origin and the other at x=0.600m, as shown in Fig 21.36. Find the position on the x-axis where the net force on a small charge +q would be zero Homework...

Homework Statement I have physics homework and i don't quite seem to understand the question: Two objects ( X and Y ) are placed at a distance of .800m from each other. The charge on X is 6.65000x10^-6 C and Y is 7.73000x10^-6. What is the value of electrical force (in Newtons) between the two...

Hi there, I have a question about Coulomb's Law. Assume there is a uniform sphere charge distribution RHO and I want to know the electric field at some point inside the sphere. I can simply apply Coulomb's Law to find it. However, I worry about the contribution from source point that is...

Homework Statement A point charge +q is located a distance d from one end of a uniformly charged rod. The rod has total charge +Q and length L. (The rod and the point charge are each held fixed in place.) What is the force on the point charge due to the rod...

Homework Statement Two charged spheres, 10.0 cm apart, attract each other with a force of magnitude 3.0 x10^-6 N. What force results from each of the following changes, considered separately? An uncharged, identical sphere is touched to one of the spheres and is then taken far away...

[b]1. Homework Statement [http://img44.imageshack.us/img44/1104/58339946.jpg ][/URL] [b]2. Homework Equations [F=k*abs(q1)*abs(q2)/r^2] [b]3. I understand the equation, but I am having trouble with my signs and also how to include the distance in the equation. I know that the...

I have a quick question about using Coulomb's Law, and I was hoping someone would be able to help me. There are two identical charges which are one meter apart that are repelling each other with a force of 1 N each. What is the magnitude (Coulombs) of each charge? I tried using Coulomb's law...

I read in the Feynman Lectures, section 5-8 in Volume 2, that Coulomb's law may begin to break down at distance scales shorter than 10^-14 cm. Feynman says that, at the time of his lecture, the question was still open. Does anyone have any new information on this question? Thanks, Djinn

Homework Statement I just have a quiz, but i don't get this question this is all i can remember A=-4.0*10^-6C B=+2.5*10^-6C mass of sphere: 51g initial separated distance:10.0cm If A and B touch and then repel, what is the new separated distance After they touch, Tension force on the string is...

Coulomb's Law lab , please help, it do tommorrow Homework Statement Here is the picturehttp://img407.imageshack.us/img407/933/48460315.jpg Distance(cm) radius(cm) 0.2 1.4 0.4 1.4 0.8 1.35 1.0 1.35 1.2 1.3 This is...

Coulombs Law ! Please Help Homework Statement Two metal balls A and B of negligible radius are floating at rest on Space Station Freedom between two metal bulkheads, connected by a taut nonconducting thread of length 1.30 m. Ball A carries charge q, and ball B carries charge 2q. Each ball...

Homework Statement A charged particle A exerts a force of 2.62 micro Newtons to the right on charged particle B when the particles are 13.7 mm apart. Particle B moves straight away from A to make the distance between them 17.7 mm. What vector force does it exert on A? using coulombs law...

Coulomb's law says that the electrostatic force between two electric charges is given by the formula: Ke*q1*q2/r^2 So, what I want to know is: 1. How did he figure out that Ke was equal to 1/(4*pi*electric constant)? I mean, I know he used a torsion balance to perform measurements in...

Coulomb's Law on a line...again. Homework Statement Homework Equations E=\frac{kQ}{d^2} The Attempt at a Solution I've been working on this one for three days now and can't come up with a valid answer. I've broken this problem up into two sections, one for the upper ring...

Coulomb's Law... Can anyone please tell me why is Coulomb's Law applicable only to the point charges?

1)What is the formal definition of a point charge? It is known, that coulomb's law , is valid for point charges? But the real world does not consist of point charges. And coulomb himself used two spheres in his experiments... 2)Another point, in many books I have found that they say, when...

Homework Statement When a -9.0 micro-coulomb charge is placed 0.12 cm from a charge q in a vacuum, the force between the 2 charges is 850 N. What is the value of q? Homework Equations F = kq1q2/r2 The Attempt at a Solution q2 = Fr2/kq1 q2 = (850 N)(0.0012 m2)/(9.00 x 109...

Four point-charges are fixed at the corners of a 3.0m X 4.0m rectangle. The coordinates of the corners and the values of the charges are listed below. q1 = 100 microC (0, 4m), q2 = 36 microC (4m, 3m), q3 = 125 microC (0, 3m) and q4 = 32 microC (0,0). Compute the net electrostatic force acting on...

Homework Statement I've taken the liberty to translate the problem, along with its corresponding diagram, into an image: http://img15.imageshack.us/img15/9695/questionm.jpg angle q1 = 53* angle q2 = 37* angle q3 = 90* Homework Equations F21 = kq1q2/(r21)^2 F31 = kq1q3/(r31)^2...

Homework Statement Consider the two parallel electric dipoles shown. + (Q) + (Q) | (Distance=d/2) ------------------------------------------x------ - (-Q) - (-Q) | (Distance=d/2)...

Homework Statement Consider a segment of a molecule of DNA that is a coil with an overall length of 2.1*10^-6 m. If the ends of the molecule become singly ionized (one end loosing a single electron and the other end gaining a single electron) the helical molecule acts like a spring and...

If I have a positive and negative charge, say -1C and +1C, will the force of attraction be the same as the force of repulsion for a +1C and a +1C charge? I've been trying to teach this electrostatics chapter to myself before term commences so I can get a bit of a head start.

Homework Statement Given: Two similar tiny balls of mass M are hung from silk threads of length L and carry equal charges q. An angle is formed where the two threads meet which we'll call \phi (This angle is actually divided in half and each half is called \theta) Assume that \theta is...

Homework Statement What are the magnitude and direction of the electric field at a point midway between a -9.0 µC and a +6.0 µC charge 3.0 cm apart? Assume no other charges are nearby. Homework Equations Fe= {K(q1)(q2)}/d^2 k = (8.99 x 10^9) The Attempt at a Solution First I...

Homework Statement Nobel laureate Richard Feynman once said that if 2 persons stood at arm's length from each other and each person had 1% more electrons than protons, the force of repulsion between them would be enough to lift a "weight" equal to that of the entire Earth. Carry out an...

Homework Statement A particle with charge −9 μC is located on the x-axis at the point 8 cm, and a second particle with charge 5 μC is placed on the x-axis at 6 cm. The Coulomb constant is 8.9875 × 109 N · m2/C2. What is the magnitude of the total electrostatic force on a third particle with...

Homework Statement Particle 1 of charge q1 = +0.76 µC and particle 2 of charge q2 = -3.0 µC, are held at separation L = 13 cm on an x axis. If particle 3 of unknown charge q3 is to be located such that the net electrostatic force on it from particles 1 and 2 is zero, what must be the x and...

Homework Statement The drawing shows three point charges fixed in place. The charge at the coordinate origin has a value of q1 = +8.02 C; the other two have identical magnitudes, but opposite signs: q2 = -4.73 C and q3 = +4.73 C. (a) Determine the net force exerted on q1 by the other two...

Homework Statement Two spherical objects are separated by a distance of 1.98 x 10-3 m. The objects are initially electrically neutral and are very small compared to the distance between them. Each object acquires the same negative charge due to the addition of electrons. As a result, each...

In Feyman's lectures on physics, he said Maxwell's first 2 equations in electrostatics, namely curl E =0 and div E=rho/epsilon, is equivalent to Coulomb's law and superposition principle, But for a particular charge distribution, we can always use Coulomb's law and superposition principle to...

This may not be a challenge for some of you, but it is hard for me as I just got introduced to the topic, your help will be appreciated. It is about Electric Force. Coulomb's Law. Homework Statement Charges of -1 micro coulomb and -4 microcoulomb are placed at opposite ends of a meter ruler...

I need a lot of help with Coulomb's Law and Electric Fields?? Need HELP! Homework Statement Here are 3 of the 25 questions the i did not understand, in regards with electric fields and Coulomb's Law. 1. A small object of mass 2.0 g and charge of 1.8x10^-7 C "floats" in an electric field...

3 equal charges q are at the vertices of an equilateral triangle as shown, with the z-axis running through the midpoint of the triangle (such that the distance from each charge to the midpoint is d) http://img111.imageshack.us/img111/7159/graphieew7.th.jpg a bead of charge Qb (of equal...

Homework Statement 3 Point charges are fixed in place in a right triangle. What is the electric force on the +1.0 nanoC charge due to the other two charges? Basically you have 3 charges in a right angle as decribed, let's call them A, B, and C. In the upper left you have A, +0.8 nanoC...

Hey. I only just started this unit at school (after coming back from holidays and forgetting everything!) and I'm having trouble with the following problem: Homework Statement "Four point charges A, B, C and D are arranged on the corners of a square of side 25cm. If A and B each have...

Homework Statement three point charges are placed at the following points on the x-axis +2 uC at x=0, -3uC at x=40 cm, -5 uC at x=120 cm. find the force (a) on the -3 uC charge, (b) on the -5 uC charge ans. (a) -0.55N ; (b) 0.15 N uC=nano coulomb Homework Equations Fm=qvB ...

Hi, I want to calculate the potential energy between two opposite charges (a dipole) and I know how to integrate Coulomb’s law in the polar form, i.e. in terms of “r” \[...

Homework Statement In the figure 21-29, particles 2 and 4, of charge -e, are fixed in place on a y axis, at y2 = -7.20 cm and y4 = 16.6 cm. Particles 1 and 3, of charge -e, can be moved along the x axis. Particle 5, of charge +e, is fixed at the origin. Initially particle 1 is at x1 = -9.84...

Homework Statement A dust cobweb is drawn from an initial vertical position toward a nearby wall by an electrostatic force. Assume the cobweb to be like a single dust ball of mass 2.0 x 10-7g suspended on a massless string of length 0.42 m connected a horizontal distance of 0.35 m from the...

Homework Statement What is the force F on the 1.0 nC charge in the figure? Give your answer as a magnitude and a direction. Homework Equations The Attempt at a Solution Applying coulomb's law for the 1.0 nC charge and the 2.0 nc Charge: F= kq1q2/r^2...

Homework Statement In the figure below, determine (a) the electric force on 10 micro Coulomb due to other charges, and (b) the electric force on 2 micro Coulomb due to other charge Homework Equations Coulomb's Law Fe = kq1q2/D² k = 9.0 x 10^9 The Attempt at a Solution I really...

Homework Statement Homework Equations F = | kqQ / r*r | The Attempt at a Solution Magnitude: F_net = F_1on3 + F_2on3 F_1on3 = (9E9)(70E-6)(15E-6) / ( (sqrt(5))^2 ) = 1.89N F_2on3 = (9E9)(-36E-6)(15E-6) / ( (2)^2 ) = -1.215N ~ -1.22N F_net = 1.89 - 1.22 = 0.67N Direction =...

Homework Statement By what factor must you change the distance between two point charges to change the force between them by a factor of ten? Homework Equations F1=kq1/r^2 F2=kq2/r^2 The Attempt at a Solution F1:F2= 10 r1/r2=sq.root(F2/F1)= 1/sqroot10 I do not understand...

Homework Statement Consider the arrangement of point charges shown below. Calculate the net force on point charge 1 given the arrangement of the point charges and the separation of the charges. 1=2=3=e- 2=e+ r=0.4cm =0.0004m K=9x10^9 Fnet=? Please use this link for an image of...

There are four charges, each with a magnitude of 2.5 microcoulombs. Two are positive and two are negative. The charges are fixed to the corners of a 0.29-m square, one to a corner, in such a way that the net force on any charge is directed toward the center of the square. Find the magnitude of...