What are caustics as they apply to optics?
I've searched the web for caustics and optics, but mostly see pictures of them. They seem to have some positive use. In some fashion they seem to magnify. They seem to be somehow related to critical...
View ArticleWhat hath Newton wrought in the two centuries after his death?
I know that Newton's work made possible the Industrial Revolution, but I don't know how. I understand his impact on subjects like astronomy, gravity, and predicting motion, but not on mechanics and...
View ArticleWhy do we need to integrate to find electric field?
Hi, I never really understood this fundamental concept of integration of rings to find the electric field for say a flat disk. In my book to find the electric field on a point charge on the axis of a...
View ArticleHow is work dependent on displacement rather than distance?
Using the definition of work=force x displacement (which I understand is correct):If I push a box along the ground with force of 10N over a distance of 1m and then back again to the starting point, the...
View ArticleWhat does 'k' in Newton's law of cooling represent?
Newton's law of cooling says: Instantaneous rate of cooling = -k (Original temperature - Final temperature) But what does this 'k' mean? I know it depends on the nature of the surface; but what...
View ArticleTotal Charge on Conducting Hollow Sphere
I've just worked out using the method of images that the total induced charge on a grounded hollow conducting sphere in the presence of a dipole outside the sphere pointing in the radial direction is...
View ArticleScience Fair Ideas?!
Hey guys, our teacher just announced that for our physics final this year we will be participating in our first ever school science fair (ooohhh!) Anyways, I've been searching for an hour or so and...
View ArticleConceptual Q: Angular Momentum
L = r x p What's the significance of angular momentum, L, acting along the z axis? Angular momentum is being compared to translational momentum, p = mv, but translational momentum is acting the same...
View ArticleDoubts on rotation
I have some doubts on topics related to rotation, so I thought I'd make a single thread rather than multiple ones. 1. Why are the Coriolis and Centrifugal forces "fictitious"? I think I might be...
View ArticleSimplified form of Voltage Formula
In my book it gives the relationship between voltage and electric field as Vb-Va= -[itex]\int _a^{b}[/itex] E dl which for a positively charged conducting sphere Q simplifies to...
View Articlecharge density
Hello, I am confused about how charge density is only related to the material of a conductor and not on any external factors. I don't see how the molecular weight, density, and avogadro's number...
View Articlefree gibbs energy doubt
I´m having serious problems with free gibbs energy equation. My main problem is that i dont know the meaning of TΔS that appears in free gibbs formula. I know that S is entropy and T temperature; but...
View ArticleQuestion?
A river flows with a velocity of 3 m/s east. The river is 300 m wide. A boat is moving 10 m/s due north. If the river flow is not corrected for, how far will the boat have moved downstream by the time...
View ArticleChanges in volume change total force?
Pressure=Force/Area If you had a cube, with a volume of one cubic inch, that means that each side would be one inch. As a cube, it would be like a die, and therefore have 6 sides, and 6 square inches....
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Please explain why one of the integral vanishes
[IMG][/IMG] This is a elemental magnetic dipole. The book shows how to find the vector magnetic potential at any distance from the origin. If you read the bottom, it said the second integral in 11.24...
View Articlespeed of light and snell's law
Hi, We know that light changes speed when going from a medium 1 to medium 2 (obviously, they are characterized by different driffactive indexes). Light wavelength doesn't change (same color) during...
View ArticleWhat happens in non-uniform circular motion?
Hi, Say there's a particle moving with just a radial component of acceleration, this will stay in circular motion because the acceleration is always perpendicular to the velocity. But if you introduce...
View ArticleBrownian Particle bound by a Spring / internal Energy
Hi, i regard a Brownian Particle connectet to a Spring and there is a heat-reservoir. The distribution of the x-coordinate of the particle follows the Diffusion-Equation (Fokker-Planck-Equation):...
View ArticleA ride on the Shuttle
Yesterday I got fascinated by the camera recordings on the Atlantis Space Shuttle. http://www.youtube.com/watch?v=2aCOyOvOw5c I have two questions which I cannot give an answer. Maybe some of you may...
View ArticleSound waves: How do we know it is the fundamental harmonic?
I have done a handful of problems related to sound waves in air columns and one thing I have noticed is that, unless told otherwise in the problem formulation, one always assumes that sound wave that...
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