What is Electrostatic force: Definition and 184 Discussions

Coulomb's law, or Coulomb's inverse-square law, is an experimental law of physics that quantifies the amount of force between two stationary, electrically charged particles. The electric force between charged bodies at rest is conventionally called electrostatic force or Coulomb force. The law was first discovered in 1785 by French physicist Charles-Augustin de Coulomb, hence the name. Coulomb's law was essential to the development of the theory of electromagnetism, maybe even its starting point, as it made it possible to discuss the quantity of electric charge in a meaningful way.The law states that the magnitude of the electrostatic force of attraction or repulsion between two point charges is directly proportional to the product of the magnitudes of charges and inversely proportional to the square of the distance between them,





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F

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=

k

e






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q

1



q

2



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r

2






{\displaystyle |F|=k_{\text{e}}{\frac {|q_{1}q_{2}|}{r^{2}}}}
Here, ke is Coulomb's constant (ke ≈ 8.988×109 N⋅m2⋅C−2), q1 and q2 are the signed magnitudes of the charges, and the scalar r is the distance between the charges.
The force is along the straight line joining the two charges. If the charges have the same sign, the electrostatic force between them is repulsive; if they have different signs, the force between them is attractive.
Being an inverse-square law, the law is analogous to Isaac Newton's inverse-square law of universal gravitation, but gravitational forces are always attractive, while electrostatic forces can be attractive or repulsive. Coulomb's law can be used to derive Gauss's law, and vice versa. In the case of a single stationary point charge, the two laws are equivalent, expressing the same physical law in different ways. The law has been tested extensively, and observations have upheld the law on the scale from 10−16 m to 108 m.

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  1. P

    Solve Electrostatic Force Problem

    TITLE: Hard Electric Charge Problem. Homework Statement 15. The charges and coordinates of two charged particles held fixed in an xy plane are q_{1} = +3.0 \muC, x_{1} = 3.5 cm, y_{1} = 0.50 cm, and q_{2} = -4.0 \muC, x_{2} = -2.0 cm, y_{2} = 1.5 cm. Find the (a) magnitude and (b)...
  2. C

    Deriving equation for electrostatic force.

    Homework Statement Basically I am given an image showing a test charge tied to a string where there is the ball is stationary. I need to use the fact that there is no net force on the ball to derive an equation for the electrostatic force in terms of g, the angle, and the mass of the ball...
  3. B

    Electrostatic force problem in Newtons

    Three charges are fixed to an xy coordinate system. A charge of +14 uC is on the y-axis at y= +3 m. A charge of -14 uC is at the origin. Lastly a charge of +47 is on the x-axis at x= +3 m. Determine the magnitude and direction of the net electrostatic force on the charge at x= +3 m. Specify...
  4. P

    Electrostatic force and # of elementary particles

    I need to find the electrostatic force & the number of elementary particles between two charged balloons held in the center of their strings (Think of an Isosceles Triangle). Homework Statement Mpurple(balloon) - .00354 kg Mred - .00405 kg Lpurple - .725 m Lred - .68 m θ = 16° T =...
  5. V

    Y-component of Electrostatic Force

    Homework Statement Calculate the X, Y, and magnitude force between the two charges. Compare to the computer simulation results. Homework Equations Do not forget that this is a 2-D problem. Use the 2-D Coulomb’s law for line charges. The Attempt at a Solution Basically we used a...
  6. young physical

    Electrostatic force on the particle

    if a charged particle ic located inside a shell of uniform charge there is no net electrostatic force on the particle from the shell. 1st is this fact? 2nd if it is so please explane it to because there is some distance between the particle and other chargeds in shell every one has different...
  7. L

    Motion under repulsive electrostatic force

    Is there a simple curve that 2 particles follow when there's a repulsive electrostatic force - like there is for gravitational forces? I don't know how to solve the differential equation that you get for the motion. Laura
  8. M

    Coulombs Law and electrostatic force

    Identical isolated conducting spheres 1 and 2 have equal charges and are separated by a distance that is large compared with their diameters. The magnitude of the electrostatic force acting on sphere 2 due to sphere 1 is F = 8.9 N. Suppose now that a third identical sphere 3, having an...
  9. E

    How does quantum mechanics affect the classical electrostatic force?

    I read Feynman's quantum electrodynamics, but I do not clearly understand, where quantum mechanics enter. So if clasicaly force in electrostatic field equals F = e^2 /4 pi epsilon 0 r^2. What happens, when quanum mechanics is included. I think that for elementary principle we do need...
  10. S

    Equilibrium: Electrostatic force and Gravitational force

    Two identical balls of mass 38 g are suspended from threads of length 1.5 m and carry equal charges of 16 nC as shown in the figure. Assume that θ is so small that its tangent can be replaced by its sine and find the value of x. (picture attached) I know that the sum of all the forces must...
  11. V

    Electrostatic Force Between Conductor and Insulator

    Hi, I have the following question: An uncharged wooden stick is balance on a pivot so that it can rotate freely. If a charged rod is brought close to one end of the stick, the stick will be... Attracted by the charged rod is the answer. This has got me confused for a while. Here is my...
  12. B

    Electrostatic force on nonlinear charges

    http://www.imagebucket.net/images/bigslowy/physicsproblem.jpg What is the strength of the electrostatic force on the top charge? Answer in units of N. I tried breaking it down into components of Fabx + Fbcx ect. but I still don't get a correct answer. Is there a different approach I...
  13. D

    Find the magnitude of the electrostatic force

    I am having difficulties with the following problem. I have gotten parts (a) and (b) (my correct answers are shown below), but I cannot figure out how to do part (c). Any help with it would be greatly appreciated. Thanks! ------------ The charges and coordinates of two charged particles...
  14. F

    Net electrostatic force : four particles form a square

    I apologize in advance - I am completely clueless about this one. I thought I had it figured out, but it turns out that I think I don't know where to even start. Four particles form a square. The charges are q1 = q4 = Q and q2 = q3 = q. What is Q/q if the net electrostatic force on particles...
  15. E

    Solving an Electrostatic Force Problem

    I'm stuck on the following problem: Point charges of q_1=-12nC are placed at (-4,0) cm and (4,0) cm. Determine the magnitude of the electrostatic force on a third charge of q_2=20nC placed at (0,8) cm. So because of symmetry I figured that the x-components of the forces will cancel each other...
  16. L

    Electrostatic force and virtual photon exchange

    Hello, although being graduated in physics (but not being an expert on QED) I find myself embarassed in trying to explain in very simple terms how the electrostatic force arise from the exchange of virtual photon. Especially when it comes to actually reduce all calculations to the expected...
  17. M

    Understanding Electrostatic Force: Q&A

    Can someone explain this law to me in simple terms? I know that it is the electrostatic force between 2 charged objects in relation to the quantity and inversly related to the square of distance F=K q1 q2 / d^2 ..but what if you have atoms that are spearated by a certain distance and have...
  18. M

    Finding the net electrostatic force on particle 1, triangle

    Hello everyone, Did I do the 2nd part of this problem correct? Part B. I boxed in the answer, i think it will just be easier by showing you my drawing so here is the picture -> http://img221.imageshack.us/img221/9340/phsyicss9lb.jpg thanks!
  19. R

    Direction and magnitude of the net electrostatic force

    Find the direction and magnitude of the net electrostatic force exerted on the point charge q2 in Figure 19-31. Let q = +1.8 µC and d = 41 cm. Direction ° (from the x-axis, which points to the right) Magnitude N *image of diagram* http://www.webassign.net/walker/19-31.gif
  20. J

    Electrostatic force electroscope

    electroscope A large electroscope is made with “leaves” that are 78-cm-long wires with tiny 24-g spheres at the ends. When charged, nearly all the charge resides on the spheres. If the wires each make a 3.0E1° angle with the vertical (see figure), what total charge Q must have been applied to...
  21. R

    Time as a function of distance? electrostatic force

    time as a function of distance? electrostatic force C = coulombs, Ke = electrostatic constant, d = distance, m = mass of electrons, v = velocity, c = a constant F(d) = (KeC^2)/d E(d) = (KeC^2) * integral (1/d) dd = KeC^2(lnd2 - lnd1) E = 1/2 mv^2 v = sqrt(2E/m) =...
  22. J

    Maximum electrostatic force problem

    im studyng electromechanics and this is a problem i found gived a fixed point A charged with Q1 charge, gived a electrical wire of fix length L and charge Q2 distributed uniformly in it, the wire is fixed at its edges at 2 points along a line L, the line L and the point A are separated by...
  23. S

    Calculating Electrostatic Force of 3 Point Charges

    Three identical point charges of 2 micro C are placed on the x-axis. The first charge is at the origin, the second to the right at x = 50 cm (.5 m), and the third at the 100 cm (1 m) mark. What are the mag. and direction of the electrostatic force which acts on the charge on the origin? The...
  24. L

    How Does Electrostatic Force Affect Neutral and Charged Spheres?

    Sphere A carries a net charge and sphere B is neutral. Both are conducting spheres and they are placed near each other on an insulated table. Which statement best describes the electrostatic force between them? a) there is no force b/w them since one is neutral b) there is a force of...
  25. A

    Electrostatic Force Derivitive

    Well,I've tried attempting this problem but I am not sure if I approached it the right way. Here is a link for the diagram and the question. [PLAIN]http://img.photobucket.com/albums/v367/crazy_cat_lady/physics/diagram1.bmp[/URL] If anyone could check it over and point out any mistakes...
  26. M

    How Does Electrostatic Force Affect Charges Within a Uniformly Charged Sphere?

    Consider a solid sphere of radius R containing a total charge Q which is uniformly distributed throughout the volume with a volume charge density rho. a) find the total force exerted by the electrostatic field on the charge in the 'northern hemisphere'. express your answer in terms of the...
  27. F

    Electrostatic force, Newtons and Distance

    Have a problem that I'm not sure how to approach any help would be appreciated! If the electrostatic force between two protons is equal to 1x10^-7 Newtons, what is the distance between them?
  28. A

    Confused: Determining Net Electrostatic Force and Direction

    Could someone please help me figure out how to determine the net electrostatic force and direction in this question? I have completed what I believe to be the first portion using Coulomb's Law for the force acting on the origin charge (F12 and F13) A charge of -3.0 micro C is fixed at the...
  29. P

    How Do You Calculate Electrostatic and Gravitational Forces in a Helium Ion?

    Can someone help me with this problem: Consider a simplified model of the singly-ionized helium atom, He+: 2 protons plus 2 neutrons in the nucleus, "orbited" by one electron at a constant distance of 2.65 x 10^-11m. a. What is the magnitude of the attractive electrostatic force between...
  30. Rockdog

    Electrostatic force problem help with vector parts

    I've included a picture. Two charges Qc and -Qc(Qc = 4 µC) are fixed on the x-axis at x = -7 cm and x = 7 cm, respectively. A third charge Qb = 5 µC is fixed at the origin. A particle with charge q = 0.3 µC and mass m = 5 g is placed on the y-axis at y = 14 cm and released. There is no...
  31. Rockdog

    Electrostatic force problem help with vector parts

    I've included a picture. Two charges Qc and -Qc(Qc = 4 µC) are fixed on the x-axis at x = -7 cm and x = 7 cm, respectively. A third charge Qb = 5 µC is fixed at the origin. A particle with charge q = 0.3 µC and mass m = 5 g is placed on the y-axis at y = 14 cm and released. There is no...
  32. M

    What Charge Must an Oil Droplet Have to Balance Gravity in an Electric Field?

    Don't know where to go Get stuck at every corner. Here it is "A small droplet of oil of 50^10*-6m radius is sitting inside of an electric field 500^10*3 N/C which is pointing straight up. What must be the charge on the oil droplet so that the electrostatic force cancels out due to gravity? The...
  33. G

    Strong Nuclear Force and Electrostatic Force

    there are two forces, the nuclear force which binds protons and neutrons together. However as the size of the nucleus gets larger the electrostatic force of repulsion in the nucleus overcomes the strong nuclear force. so larger atoms breakdown to form smaller atoms, why does the electrostatic...
  34. I

    Electrostatic Force Question: Am I Right?

    Here is the question... A pith ball of mass 1.5g is suspended along a string which is attached to a non movable point, when a pith ball of equal charge and mass is brought close to the original pith ball. A state of equilibrium is reached and the pith balls are 2.6cm apart and the string...
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