Recent content by conquerer7
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Graduate Can Light Travel Faster Than c in Diamagnetic Materials?
The speed of light in vacuum is 1 / sqrt(mu_0 e_0). In matter, this is modified using relative permittivity and permeability, so the speed of light in matter is c / sqrt(k_m k_e). In diamagnetic materials, isn't k_m < 1? Then we'd have light going faster than 3 * 10^8 m/s in, say, nitrogen...- conquerer7
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- Diamagnetic Ftl Materials
- Replies: 2
- Forum: Electromagnetism
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E field outside a current carrying wire
5th edition of HRK's Physics, chapter 38, problem 11.- conquerer7
- Post #5
- Forum: Introductory Physics Homework Help
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E field outside a current carrying wire
Would this have anything to do with special relativity? I remember seeing something about length contraction when switching reference frames once, and about how that produced a charge density out of nowhere. Edit: what if there's a nonzero resistance?- conquerer7
- Post #3
- Forum: Introductory Physics Homework Help
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E field outside a current carrying wire
Homework Statement One step in one of the problems in my book (involving calculation of the Poynting vector) asks to find the electric field outside a wire. This wire is resistanceless and the current is steady. Homework Equations Maxwell's. The Attempt at a Solution Stared at...- conquerer7
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- Current Field Outside Wire
- Replies: 5
- Forum: Introductory Physics Homework Help
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Finding the amplitude in simple harmonic motion
Your initial observation was good; using this equation is overkill. But, using it: The block starts at the farthest point, so the phase constant is zero. So x(t) = A cos(ωt) Now, if you wanted to find the position at time t = 0, you'd have x(0) = A cos(ω0) = A cos(0) They told you...- conquerer7
- Post #3
- Forum: Introductory Physics Homework Help
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Circuit and Shielding Problems
Two tricky MC problems from Halliday/Resnick: 1. A point charge is placed inside an uncharged spherical conducting shell, somewhat off center. However, the charge distribution on the outer surface of the shell is uniform. Why? 2. What is the minimum number of resistors necessary to make a...- conquerer7
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- Circuit Shielding
- Replies: 1
- Forum: Introductory Physics Homework Help
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Undergrad Vertical mass-spring system - force or energy?
The first one is correct in general (i mean, unless the spring itself has mass, but that would be ridiculous!). It's just Hooke's Law. The second one is more complex. Imagine quickly hooking on the weight: the weight is going to start oscillating on the spring, with the center of oscillation...- conquerer7
- Post #2
- Forum: Mechanics
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Undergrad Charge Distribution on Two Neighboring Conductors
Say you have two spherical conductors, of radius r, centers a distance d apart. Both have charges of +Q. What are the charge distributions on them? My physics book more or less handwaves and says it'll be more or less unaffected, but is there a way to solve this exactly?- conquerer7
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- Charge Charge distribution Conductors Distribution
- Replies: 2
- Forum: Electromagnetism
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Understanding the Potential of a Conducting Sphere Lowered into a Conducting Can
Alright, that makes sense. Is this reasoning right? The potential of the can is raised, since negative charge moves to the inside to balance out the sphere's charge and positive charge moves to the outside. The can was at V = 0 previously because it was uncharged, but now V > 0. The...- conquerer7
- Post #3
- Forum: Introductory Physics Homework Help
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Understanding the Potential of a Conducting Sphere Lowered into a Conducting Can
What do they mean when they refer to it? The PE of a system, I get, and the potential of a point is the work per unit charge needed to bring a charge there, assuming the charge has no effect on the field (right?). A small conducting sphere originally has a charge +q. The sphere is lowered...- conquerer7
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- Potential
- Replies: 2
- Forum: Introductory Physics Homework Help
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Undergrad Confusion: Van de Graaff generator
My physics book explains a van de Graaff in this way: A small conducting sphere of radius a and carrying charge q is located inside a larger shell of radius b that carries charge Q. A conducting path is momentarily established between the two conductors, and the charge q then moves entirely to...- conquerer7
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- Confusion Generator Van de graaff
- Replies: 1
- Forum: Mechanics
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MV Calc Book for E&M: Best Options for Rigor & Theory
I want a MV Calc book that has a good covering of vector field operations, mostly for studying Maxwell's equations and stuff later on. Rigor would be nice; I would prefer a book that proves most theorems, but not one as crazy as Spivak (I have only a few months!). Interesting theoretical...- conquerer7
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- Book E&m
- Replies: 2
- Forum: Science and Math Textbooks
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How Are Parametric Equations for a Hypocycloid Derived?
Homework Statement Find parametric equations for the hypocycloid that is produced when we track a point on a circle of radius 1/4 that rotates inside a circle of radius 1. Show that these equations are equivalent to (sin^3 t, cos^3 t). Homework Equations N/A The Attempt at a Solution I...- conquerer7
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- Replies: 1
- Forum: Precalculus Mathematics Homework Help
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Pendulum (Conservative Forces and Potential Energy
No problem- that's what this forum is for!- conquerer7
- Post #5
- Forum: Introductory Physics Homework Help
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Motion in 1 dimension easy question?
x = t (v_i + v_f) / 2- conquerer7
- Post #4
- Forum: Introductory Physics Homework Help