Electrostatic force Definition and 184 Threads

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

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q

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q

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r

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{\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. B

    How Do You Calculate Electrostatic Force Between Charges?

    Two positive point charges, each of which has a charge of 1.5 × 10−9 C, are located at y = +0.50 m and y = −0.50 m. The Coulomb constant is 8.98755 × 10^9 N · m2/C2. a) Find the magnitude of the resultant elec- trical force on a charge of 1.0×10−9 C located at x = 0.55 m. Answer in units...
  2. Ranku

    Meaning of formula of electrostatic force

    The formula for Coulomb's force is F = k \frac{q_{1}q_{2}}{r^{2}}, which represents how the force varies as the inverse square of distance between like or unlike charges. Does it mean the repulsive force between like charges decreases as the inverse square of distance?
  3. K

    What is the work done by the electrostatic force

    Homework Statement A spherical shell of radius 'a' and charge Q is expanded to radius 'b'. What is the work done by the electrostatic force in this process? Homework Equations Method 1 Work done = initial energy - final energy Method 2 Work done = Q (potential difference between...
  4. S

    Electrostatic force problems, help

    Electrostatic force problems, help urgent! Homework Statement Question: An isolated hollow metal sphere of radius 40 cm carries a charge of -10*10^-6. What is the magnitude of the electric field E (a) in the empty space inside the sphere and (b) 60 cm from the center of the sphere ( no...
  5. K

    Electrostatic force betwen two ions

    Homework Statement A. Find the electrostatic force between a Na+ ion and a Cl- ion separated by 0.5 nm. B. Would the answer change if the sodium ion were replaced by Li+ and the CL ion by Br-?Explain. Homework Equations I believe you have to use Coulomb's Law...? F=k* [(/q1//q2/)...
  6. B

    Electrostatic force question with coulombs law

    Homework Statement A particle of charge of +4.20 x 10^-6 C is 12.0 cm distant from a second particle of charge of -1.70 x 10^-6 C. Calculate the magnitude of the electrostatic force between the particles. Homework Equations Coulombs law is F = (K*Q1*Q2) / R^2 where k = 8.99*10^9, q1...
  7. H

    Calculating the electrostatic force

    Homework Statement Calculate the (electrostatic) force between a Ca2+ and an O2– ion the centers of which are separated by a distance of 1.25 nm. Homework Equations I know that: Coulomb's Law is F = (k q1 q2)/r2 Attractive Force is F = (k z1e z2e)/r2 where z1 and z2 are the valence...
  8. S

    Cantilever switch based on electrostatic force

    Dear all: I am going to design a cantilever switch which is working with electrostatic (capacitive) force. I want to design that. That is to find the dimension and material of that. I was wondering if you could kindly suggest a reference for designing this. Thank you very much.
  9. C

    Ratio of gravitational/repulsive electrostatic force

    Homework Statement Calculate the ratio of the magnitude of the attractive gravitational force to the repulsive electrostatic force between two protons. Homework Equations Mass of proton = M = m = 1.672e-27 kg g = 9.80665m/s2 Q = q = 1.60219e−19 C k = 8.9875e9...
  10. O

    Calculating Net Charge on a Metal Sphere with Added Electrons

    Homework Statement A Metal sphere has a charge of +6uC. What is the net charge after 1*10^14 electrons have been placed on it? Homework Equations Single Electron - -1.6*10^-19 The Attempt at a Solution 1st. Convert +6uC to 1.6*10^-6 (is this right?) 2nd...
  11. A

    Electrostatic force on a charge

    i was reading the book of Griffin - introduction to electrodynamics. it is written that the force of charge q on Q is not only depends on the distance b.w them but also the velocity & acceleration of charge q.then i think coloumb'law is incomplete at all. it must include some quantity for...
  12. A

    Calculating Electrostatic Force with Coulomb's Law

    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...
  13. P

    Electrostatic Force: -0.7nC Charge at Origin

    Homework Statement A -0.7nC charge is located at the origin, while a 1.9nC charge is located 3.9 m away along the x-axis and a 0.8nC charge is located -1.7m away along the y-axis. The Coulomb constant is 8.98755*10^9 Nm^2/C^2. Find the magnitude of the electrostatic force on the charge at the...
  14. S

    How to Calculate Net Electrostatic Force in a Square Configuration?

    There are four charges, each with a magnitude of 1.98 μC. Two are positive and two are negative. The charges are fixed to the corners of a 0.288-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. Calculate the magnitude of the...
  15. M

    Electrostatic force of attraction between two particles

    The homework problem reads as follows: A proton and an electron are held in place on the x axis. The proton is at x=-d, while the electron is at x=+d. They are released simultaneously, and the only force that affects their motions is the electrostatic force of attraction that each applies...
  16. J

    Electrostatic Force: Learn About Its Effects

    electrostatic force! Homework Statement http://img10.imageshack.us/img10/3914/picture0117.jpg Homework Equations The Attempt at a Solution
  17. N

    Coulomb's Law, net electrostatic force

    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...
  18. A

    Electrostatic Force Equation Help

    I'm doing a video analysis and there is a charged ball that a woman is holding and there is another charged ball hanging from a string with length L. The video is of the woman pushing the ball closer to the ball from the string and how it pushes it away and I am using LoggerPro to analyze the...
  19. K

    How Do You Calculate the Net Electrostatic Force on a Central Charge?

    Homework Statement A charge of -3.00 µC is fixed at the center of a compass. Two additional charges are fixed on the circle of the compass (radius = 0.125 m). The charges on the circle are -4.00 µC at the position due north and +5.00 µC at the position due east. What is the magnitude and...
  20. N

    AnswerSolving Electrostatic Force: Find Charge & Mass

    electrostatic force? Homework Statement Two very small spheres are initially neutral and separated by a distance of 0.50 m. Suppose that 6.2 x 1013 electrons are removed from one sphere and placed on the other. What is the magnitude of the electrostatic force that acts on each sphere...
  21. Z

    Calculating point charges and ratio of electrostatic force to weight

    Homework Statement Measurements show that a honeybee in active flight can acquire an electrostatic charge on the order of 93 pC. a)How many electrons much be transferred to produce this charge? Ne = * b) Supposing two bees, both with this charge, are separated by a distance of 12 cm...
  22. S

    Magnitude of the Net Electrostatic Force On an Oxygen Atom

    Homework Statement The water molecule forms an angle, with hydrogen atoms at the tips and the oxygen atom at the vertex (see diagram in the previous problem). Assume that the angle at the oxygen atom is Θ = 103.5o and the distance between the oxygen and the hydrogen atoms is d = 93.1 x 10-9...
  23. H

    Net Electrostatic Force on a neg charge next to a pos charge inbetween a field

    Homework Statement Two point charges, Q1 = -6.9 µC and Q2 = 1.1 µC are located between two oppositely charged parallel plates, as shown in Fig. 16-65. The two charges are separated by a distance of x = 0.38 m. Assume that the electric field produced by the charged plates is uniform and equal...
  24. A

    Net Electrostatic Force on particles

    Homework Statement Four particles form a square. The charges are q_1 = q_4 = Q and q_2 = q_3 = q. (a) What is \frac Qq if the net electrostatic force on particles 1 and 4 is zero? (b) Is there any value of q that makes the net electrostatic force on each of the four particles 0...
  25. F

    Finding Zero Net Electrostatic Force of +ve Charge b/w q1 & q2

    Two point-like objects carry charges of q1 = +4C and q2 = -3C and are separated by a fixed distance of 50 cm. (a) Determine the point (other than infinity) at which a point-like positive charge will experience zero net electrostatic force due to the two fixed charges. q1 = +4C ...... q2 =...
  26. A

    Electrostatic Force on b: Positive & Negative?

    1. All variables and given/known data: a = c = 1 \times 10^{-19} C b = 2 \times 10^{-19} C Distance between a&b = b&c = 0.1m (b at origin, a at (0, 0.1) and c at (0, -0.1)) 2. Homework Equations : F = k\frac{|q_1||q_2|}{r^2} 3. The problem that I'm having: Am I correct to...
  27. J

    What is the Electrostatic Force on Particle 3 in a Triangular Configuration?

    Homework Statement Three charged particles form a triangle: particle 1 with charge Q1=80nC is at xy coordinates (0,3.00mm) particle 2 with charge q2 is at (0,-3.00mm) and particle 3 is at(4.00mm,0). In unit vector notation, what is the electrostatic force on particle 3 due to the other two...
  28. M

    Calculating Electrostatic Force on a Charge in a Compass

    Homework Statement A charge of -4.10 C is fixed at the center of a compass. Two additional charges are fixed on the circle of the compass (radius = 0.137 m). The charges on the circle are -3.58 C at the position due north and +6.79 C at the position due east. What is (a) the magnitude and...
  29. J

    Electrostatic force sphere problem

    The problem: Two identical conducting spheres, fixed in place, attract each other with an electrostatic force of 0.158 N when their center-to-center separation is 63.2 cm. The spheres are then connected by a thin conducting wire. When the wire is removed, the spheres repel each other with an...
  30. J

    Electrostatic force - charges jumping between objects

    So I have this homework question that I answered already but still don't understand why the answer is correct. A positively charged ball is brought close to an electrically neutral isolated conductor. The conductor is then grounded while the ball is kept close. Is the conductor charged...
  31. S

    Electrostatic Force and Superposition Principal

    Homework Statement Three charges are arranged as shown in the figure. Figure (Attached Below Could not insert the image, wouldn't work for me) Find the magnitude of the electrostatic force on the charge at the origin. Answer in units of nN. What is the angle theta betwen the...
  32. T

    Electrostatic force including coulombs law

    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 a particles. For what value of q/Q>0.5 will the electrostatic force between the two parts have 1/2 of the maximum possible value? The...
  33. H

    Could Gravity be an Electrostatic force?

    I stumbled with this paper that propose the idea that gravity could possibly be an Electrostatic force. I am no physicist but I would like to know your points of view about it, since gravity is a puzzling force. http://www.aspden.org/arp/2005arp3.pdf I have also heard about some possible...
  34. L

    Calculating Electrostatic Force: q1 and q2

    Homework Statement The charges and coordinates of two charged particles held fixed in an xy plane are q1 = +3.5 µC, x1 = 1.5 cm, y1 = 0.50 cm, and q2 = -4.0 µC, x2 = -2.0 cm, y2 = 1.5 cm. (a) Find the magnitude of the electrostatic force on q2. Done I got this part = 94.98868N (b) Find the...
  35. C

    Electrostatic force of four charged particles

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  36. B

    Strength of electrostatic force

    Homework Statement Three point charges are located at the corner of an equilateral triangle. The Coulomb constant is 8.98755 X 109 N*m2 / C2 What is the strength of the electrostatic force on the top charge? Answer in units of N. Length of each side is .19m Photo...
  37. C

    The electric field is perpendicular to the electrostatic force

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  38. A

    Can an electrostatic force repel or just attract?

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  39. A

    Calculate Electrostatic Force: Metal Spheres 3.00x10^-6C & 2.00x10^-6C @12.0cm

    Homework Statement A metal sphere with a negative charge of 3.00x10^-6C is placed 12.0 cm from another similar metal sphere with a positive charge of 2.00x10^-6C. The two spheres momentarily touch, then return to their original positions. Calculate the electrostatic force acting on the two...
  40. U

    Net Force Exerted on 4.0*10-9 C Charge at Origin

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  41. G

    Electrostatic Force of water molecule

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  42. J

    Net electrostatic force on charge between parallel plates

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  43. M

    Electrostatic Force of Water on a Chlorine Ion

    The dipole moment of the water molecule ({\rm H}_{2}{\rm O}) is 6.17 \times 10^{-30}\;{\rm C \cdot m}. Consider a water molecule located at the origin whose dipole moment p_vec points in the positive x direction. A chlorine ion ({\rm Cl}^{-}), of charge -1.60 \times 10^{-19}\;{\rm C}, is located...
  44. M

    Electrostatic Force of a hydrogen atom

    [SOLVED] Electrostatic Force Homework Statement One model of the structure of the hydrogen atom consists of a stationary proton with an electron moving in a circular path around it.The orbital path has a radius of 5.3x10^-11m. The masses of a proton and an electron are 1.67x10^-27kg and...
  45. M

    Electrostatic force between more than 2 charges

    hi i don't know if this has been posted or not but i am sort fo stuck on this one What is the force F_vec on the 1 nC charge at the bottom? View Figure Write your answer as two vector components, separated by a comma. Express each component numerically, in Newtons, to three significant...
  46. Y

    Electrostatic force between two arbitrary shapes

    I am looking some help on applying the well known formula of the electrostatic force between two parallel capacitor plates on charged surfaces which have non usual shapes. My approach is to break apart the total surface into segments with common shapes and calculating the force between each two...
  47. A

    Calculate Electrostatic Force Between Two Plates

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  48. H

    Is the Electrostatic Force Calculation Correct for Inclined Bar and Wire?

    find electrostatic force problem: there's a long straight wire with a λ1 charge. at some distance from it there's a bar charged with a λ2 charge. the bar is not parallel to the straight wire, instead it's inclined with an angle "alpha" between the dotted line, parallel to the wire, passing...
  49. P

    Electrostatic force between charges.

    Hi! we did a lab where we charged a big sphere with 5kV, with this sphere we then charged another smaller sphere that was hanging loose from a string by touching it. We had to measure the distance the small sphere moved from its initial position and also the distance from the big sphere to the...
  50. I

    Where Am I Going Wrong in Calculating the Net Electrostatic Force?

    Homework Statement Three charges are fixed to an x, y coordinate system. A charge of +18 µC is on the y-axis at y = +3.0 m. A charge of -16 µC is at the origin. Lastly, a charge of +45 µC is on the x-axis at x = +3.0 m. Determine the magnitude and direction of the net electrostatic force on...
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