Electric potential energy Definition and 175 Threads

Homework Statement Four point charges, fixed in place, form a square with side length d. (See image) The particle with charge q is now released and given a quick push; as a result, it acquires speed v. Eventually, this particle ends up at the center of the original square and is momentarily...

So.. we've got a 2D crystal, corresponding an infinite square net with +-e0 charges in each one (see the atached photo). Now I'd like to calculate the constant k..when r goes to infinity... We = k (+-e0)*(+-e0)/(4 pi eps0 r)..on the positive charge in the center caused by the negative and...

What is the electric potential energy in joules of two electrons separated by 2.68 nm?

Homework Statement (a) What is the electric potential energy in joules of two electrons separated by 2.43 nm? (b) What would be it be if the separation was doubled? Homework Equations i think v=kq/r The Attempt at a Solution (a) 1.185 J (b) 0.95 J i can't figure out what I...

Homework Statement In a model for the hydrogen atom, an electron is in circular orbit at mean distance Ro from the nucleus. Sketch U as a function of separation distance r. Write an algebraic expression for the electric potential energy U for a model of this system, i.e. charges +e and...

Homework Statement In the Bohr model of the hydrogen atom, a single electron revolves around a single proton in a circle of radius r. Assume that the proton remains at rest. a. By equating the electric force to the electron mass times its acceleration, derive an expression for the...

Homework Statement A proton is fired from far away toward the nucleus of a mercury atom. Mercury is element number 80, and the diameter of the nucleus is 14.0 fm. If the proton is fired at a speed of 4.0 times 10^7, what is its closest approach to the surface of the nucleus? Assume the nucleus...

Homework Statement A positive charge +q1 is located to the left of a negative charge -q2. On a line passing through the two charges, there are two places where the total potential is zero. The first place is between the charges and is 4.00 cm to the left of the negative charge. The second...

Hi, Homework Statement Two point charges 2.0 cm apart have an electric potential energy -149.9 µJ. The total charge is 28 nC. What are the two charges? Homework Equations U = (kqQ) / r The Attempt at a Solution U = -149.9 x 10^-6 = [(9 x 10^9)(28 x 10^-9 - q)(q)] / (0.02)...

I did all I can, and I'm stressed out over this. Thus, here I am. :( Here's the question (I substitute the numbers with alphabet letters): >Two point charges of magnitude of A nC and -B nC are separated by D m distance. >The acceleration of gravity is 9.8 m/s^2. The Coulomb constant, k, is...

Homework Statement A 0.010-kg positively-charged particle is accelerated by a uniform electric field directed to the right. The object accelerates from 5.0 to 15.0 m/s while traveling a distance of 0.10 m. Suppose the particle is moved by an external force a distance of 0.10 m against the...

could someone please lead me in the right direction with this question. I am confused about the time varying force in determining the work done A time-varying force acts on a 5 kg mass yielding a displacement x = 5t - 8t2 (x in m). The work done by the force between the times t = 0 and t =...

Following exercise: There is a one dimensional grid of infinite size and it consists of anions and cations (each with a charge of 1e / -1e) like this: acacacac The distance between the anions and cations is 5*10^-10m. Now I am supposed to calculate the electrial potential energy of one cation...

Hi, this is my first time posting here but I have a question that looked really simple at first, but the answer I get is wrong from the answer given to us by our teacher. The question is this: Consider the diagram below http://img485.imageshack.us/img485/9282/physics3bn.jpg a) What is the...

A charge of 3.19 µC is held fixed at the origin. A second charge of 3.19 µC is released from rest at the position (1.15 m, 0.530 m) . (a) If the mass of the second charge is 3.10 g, what is its speed when it moves infinitely far from the origin? ok so I've broken it up into x and y...

I can't get this question, can someone give me a hand? I will reprint the question below as it appears in the text: A Solid sphere of radius R has a uniform charge density p(roh) and a total charge Q. Derive an expression for the total electric potential energy.(Suggestion: imagine that the...

I am trying to get this concept, but I can't figure out what exactly this means. Can anyone explain what it means if something has negative electric potential energy?

the question, from the Nelson Physics 12 texbook, is : Three charges are placed at the corners of an equilateral triangle with sides of length 2.0 m. the charges, in clockwise starting at the top of the triangle are (c being coulombs) +4.0^-6 c, +2.0^-6 c, and -4.0^-6 c. a) calculate the...

This is a homework problem of a EM course: Calculate the potential energy, per ion, for an infinite one-dimensional ionic crystal, that is, a row of equally spaced charges of magnitude e and alternating sign. Hint: The power series expansion of ln(1+x) may be useful. Here's my...

"Two particles each have a mass of 6.1*10-3 kg. One has a charge of +5.0*10-6 C, and the other has a charge of -5.0*10-6 C. They are initially held at rest at a distance of 0.80 m apart. Both are then released and accelerate toward each other. How fast is each particle moving when the separation...

Electric potential energy - how is it conserved? obviously the answer is yes , its conserved.. but something bugs me about it. One particle has a mass of 3.00×10–3 kg and a charge of +8.00 mC. A second particle has a mass of 6.00×10–3 kg and the same charge. The two particles are initially...

Can some please explain the difference between "Electric potential Energy & electric potential" and when a problem is asking you to find the potential difference which is it asking for?

I've tried all three of these problems I don't know how mant times, and my work is just not correct. Any clue? The third prob, i really used some awkward equations. A particle has a charge of +1.53 mC and moves from point A to point B, a distance of 0.197 m. The particle experiences a...

Hey - just asking for some help on some electric potential energy questions. First I used the equation 1/2mv^2 = q(Va-Vb) so v = sqrt (((2)(25000)(q)) / m ) and Va-Vb = W / q, so q = W/(Va-Vb) but then I'm stuck and don't know where to go from there since the mass and the charge (q)...

I'm trying to grasp the concept between Electric Potential and Electric Potential Energy. A charge object has an electric potential, and electric potential = electric potential energy/charge I still can't explain the difference between the two(Electric Potential vrs Electric...