Recent content by Cummings

I have a problem where I need to work out a value of a specific point that lies in the quadrilateral that is formed by four separate points. For each point that makes up the quadrilateral, I know the X and Y coordinates and their value, Z. For the point I am trying to find the value for, I only...

Simplifying should never change the outcome of an equation. You can therefore check if your simplification is correct by letting x equal any number. The original and simplified equations will produce the same answer if the simplification is correct. So, let x=2 Your first equation gives (4 -...

Not really something I would expect most people to know so I will keep it out of the Homework help section (it is not homework) I am working on distributed strain sensing with fibre optic Bragg gratings for aircraft. For those that don't know, FO Bragg gratings are a periodic variation in...

This might be a bit to specalised for some of you, but i am trying to calculate the number of modes that light can propegate in a material. The question is as follows Consider a cavity that is a cube with the side length a = 1mm filled with water (refractive index(n) 1.33). Calculate the...

I am trying to derive the Fresnel equations for the E field perpendicular to the plane of incidence. There is one transformation, I assume involves some general math, that I am having a mental blank on. It can be found here http://physics.tamuk.edu/~suson/html/4323/prop-em.html if you...

we are using a university made textbook and so do not have access to anything else. The exact question is as follows Use Amperes law in integral form for a static field to find an espression for the magnetic field due to a uniform thin current sheet of infinant extent in the x-y plane with...

There is a uniform thin current sheet of infinite extent in the x,y plane. Assuming the magnetic field is only a funtion z, perpendicular to the plane and that the magnetic field direction is parallel to the plane and perpendicular to the current direction (which is in the positive x...

http://www.eweek.org/site/DiscoverE/PDFs/middle/First%20you%20see%20it%20Then%20You%20Hear%20It.pdf In my Photonics & Fibre Optics class today, our lecturer showed us a "Modern day photophone" he created for an easy $15 AUD (1AUD = 80US cents) I did not have time to ask him how to make one...

hehe..double sided elevators. My most embarrasing one would have to be getting caught by my mother, and it wasnt with a chick (or guy). Not much to say about it. She burst in, took a moment to realize then went out again. Not a single word said. I have been quite lucky with embarrasing...

Discussing it with fellow students today, the powerlines, being AC would most likely be at different voltages due to their different phases. So, that would couse the potential difference neeced to electrocute a bird.

2 things, First, I am asked to describe why a bird can sit on a powerline and not be electrocuted, yet if it spreads it's wings and touches two wires, it will be. I can understand why it can sit on one. The powerline is all at the same voltage. And so there is no potential to motivate the...

Yes, i made a few erros in that post. Had to make it to the next class of uni. Yes, the prism is in water. relinquished managed to type in what i failed to. He got the same answer to. I just for some reason replaced water with air when i typed this up. So, would 1.88 be the minumum...

The Question: A 45-45-90 prism is immersed in water. What is the minimum index or fefraction the prism must have if it is to reflect totally a ray incident normally on one of its faces. Now, we have found this question a bit hard to understand. We assume that light is hitting one of the...

Had a little project a while back, created some 'coke bottle' rockets. The ideais simple, use compressed air to push out an incompressible liquid, water creating some thrust for the bottle rocket to fly into the sky. there are plenty of tutorials for making bottle rockets out there, but i...

Now, given y=x^3 -9x^2+23x-16 on the interval [-3,7] the maximum and minimum values would be the turning points right? also, a stationary point of inflextion is where the grandient is zero, with a positive or negative gradient on both sides right? i am asked to find the EXACT values of...