Internal Definition and 957 Threads

Homework Statement [PLAIN]http://img689.imageshack.us/img689/3047/directproduct.png < denotes a subgroup. \triangleleft denotes a normal subgroup. The Attempt at a Solution Have I done (a) correctly? 0 \in A so A \neq \emptyset If a=x+ix and b=y+iy then ab^{-1} = x-y + ix...

Homework Statement Assume a star is in hydrostatic equilibrium and that the density of the star is follows \rho \propto \frac{1}{r^{a}} where \r is the distance from the centre of the star and \r is a constant. Derive an relation for the pressure of the star as a function of \r...

I have an enclosure in which the electrical components put off 10,500BTU/hr. At the top of the enclosure the internal hot air is in contact with circular aluminum tubes. Ambient outside air at 70 degrees F is blown through the center of the tubes at 500cfm. Internal hot air and outside ambient...

Homework Statement A voltmeter whose resistance is 1000 ohms measures the voltage of a worn out 1.5V battery as .9V. What is the internal Resistance Homework Equations The Attempt at a Solution In order to do this, I Solved for the Equiv Resistance of the circuit (leaving in...

For a commutative ring R and an ideal I, is it true that I \oplus R/I \cong R ? I know in some cases this is true, and I know it's true for finitely-generated Abelian groups, but is it true for any commutative ring? In other words, we know that R/I is isomorphic to some ideal in R, call this...

Homework Statement Hi I wonder if anyone can help. I am having difficulty drawing refracted and total internally reflected rays. I have an exam on Monday. Can anybody recommend good websites that can help? Slight panic. Thanks Homework Equations The Attempt at a Solution

Homework Statement A helium balloon with a volume of 1m^3 and temperature of 27 deg c is placed in liquid nitrogen in an open container and cools to a temperature of 77 K. Assume that helium behaves like an ideal gas at constant atmospheric pressure and find the new volume of the gas in the...

hello.. this is my first post..forgive me if my question is wrong.. Why does a current source is modeled in such a way that it has its internal resistance in parallel ? Why can't it have its internal resistance in series ? The question may seem awkward , but please answer me.. thanks in advance..

Homework Statement A container of volume 0.72 m^3 contains 1.4 mol of argon gas at 24 degrees C. Assuming argon behaves as an ideal gas, find the total internal energy of this gas. The value of gas constant is 8.31451 J/mol x K. Answer in units of J. Homework Equations PV=nRT...

Question about Total Internal Reflection? My textbook says that for total internal reflection to occur 2 conditions need to be met. Light is traveling more slowly in the first medium than the second medium and no.2 is the angle of incidence must be large enough for no refraction to occur. My...

Question about Total Internal Reflection? My textbook says that for total internal reflection to occur 2 conditions need to be met. Light is traveling more slowly in the first medium than the second medium and no.2 is the angle of incidence must be large enough for no refraction to occur. My...

How to calculate Energy absobed by the components of a Truck Cab after crash test?? Hi, I have a question regarding the calculation of internal energy of components after collision. In conducting the frontal impact test as per the ECE R29 regulation, a swing bob has to hit the front of...

hi, if suppose a battery is 100% charged and is capable of delivering 12V. Now if i connect a bulb of 40watts across it then their will be a voltage drop and the internal resistance can be calculated. If the same battery with 100% charge is used with a 80watts bulb then again their will be a...

Homework Statement Helium (He), a monatomic gas, fills a 0.010-m^3 container. The pressure of the gas is 6.2 multiplied by 10^5 Pa. How long would a 0.38-hp engine have to run (1 hp = 746 W) to produce an amount of energy equal to the internal energy of this gas? Homework Equations...

We known U=3/2nRT (monatomic ideal gas), just depends on temperature. Most texts assert connecting U and Q with constant volume condition and say"\Delta U = nCv\Delta T for any process because of internal energy only depends on temp". I think that statement is very strange. Deriving...

Homework Statement Two grams of water are sealed in a rigid con- tainer; then the water is vaporized by heating. 1664 cal of heat is needed for vaporization. What is the change in internal energy of the water? Answer in units of J. Homework Equations 1 kcal= 4,186 J The Attempt...

Hey people I intend to self learn IC engines. I am a a little confused by what this sentence says in my textbook. "An idling engine is one which operates at no load and with nearly closed throttle" I basically want to know what loading means in this particular context? And what else can...

Ok guys I need help! Its been a while since I last opened a physics workbook and now I'm back to studying to try and further my career and I've come across an internal resistance question that I can't get my head around! A resistance of 10.5 ohms is connected across the terminals of a battery...

hi, Can anybody explain the phenomenon behind internal energy? and what is the change in internal energy when water evaporates. Please do give reference to first law of thermodynamics. Thanks in advance.

I have the truss shown, I'm supposed to find the internal force for each of the vertical members...I understand method of joints and method of sections, but can you use both method of joints and sections in the same problem...for example I found Ly=52.5 and Ry=32.5 using moments and summing in...

Hi all, From what I understand, total internal reflection reflect 100% of light. Suppose you had a transparent material with a critical angle of 45 degrees. Now say you had a cone with a 45 degree angle, and you shined monochromatic light in through the base. Would 100% be reflected (minus...

please see the attached image, I'm supposed to find the internal force in each member of the truss. I used moments to find My=40 and Gy=120, I then moved on to FBD of joint G where I found Fgh=30kN in tension, and Fga=50kN in compression, next I did joint A to find Fab=30kN in tension...

Homework Statement an internal explosion breaks an object, initially at rest, into two pieces, one of which has 1.5 times the mass of the other. If 7500 J were released in the explosion, how much kinetic energy did each piece acquire. Homework Equations K1+K2=7500J...

Homework Statement an internal explosion breaks an object, initially at rest, into two pieces, one of which has 1.5 times the mass of the other. If 7500 J were released in the explosion, how much kinetic energy did each piece acquire. Homework Equations mgyi+1/2mvi2=mgyf+1/2mvf2 The...

Problem: Given a circle of radius 1. Take a sector of this circle with internal angle A, where 0=<A=<pi/2. Find a formula for the radius of the smallest circle that will perfectly fit this sector, as a function of A. Solution. I used laws of sine and cosine and came up with...

Homework Statement Show that internal energy U = U(T) only for an ideal gas who'se equation of state is: P(V-b) = RT (the claussius equation for n moles of gas) Homework Equations Thermodynamic Equation of state: \left(\frac{\partial U}{\partial V}\right)_T =...

Hi, I had a question about Torque, Internal forces & external forces. Here are 2 examples helping me to state my question: 1) The Earth is rounding the sun with respect to the Sun. The forces which are acting on the system are 2 gravitational forces that are action & re-action. The Force...

Why is internal energy not sufficient to compare states? Thank you for your answer.

Hi! I'm trying to fully grasp why the potential drops when an internal resistance is present in a source of emf. At first I thought that yes it would be harder to "push" the charges to the higher potential, but once there, why shouldn't the higher potential be the same as before? Just as if a...

When light approaches and enters a material, why does all the reflection happen at the surfaces? I mean, light is coming at say, some crystalline solid. It hits the first plane of atoms and some is reflected. Some goes into the crystal and passes through the 2nd, 3rd, 4th,..., (n-1)th plane of...

Something has been bugging me for a long time, since I took my first statics class a few years ago. I have a problem with a common figure found in many statics books. I have attached the figure to my post. My question deals with the delta V added to the shear force on the right side of the...

I have an spark ignited 4 cylinder 2000 cc engine in a wagon and I think its 50% thermally efficient at idle due to the mods I have done on the intake manifold. My engine uses (mesured on video) roughly 9.807 cc/min at approx 750 rpm and the only reference I have come across is a similar...

Is the internal energy for a closed cycle always zero?

When a battery is connected to a 110.-ohm resistor, the current is 3.98 A. When the same battery is connected to a 400.-ohm resistor, the current is 1.11 A. Find the emf supplied by the battery and the internal resistance of the battery. Equations: Vemf = i*R I'm not sure how...

what is the difference between external and internal circuit? advanced thanks

Hi, 1. \color{blue}dq=dU+PdV so C_V = \left(\frac {\partial q}{\partial T}\right)_V= \left(\frac {\partial U}{\partial T}\right)_V leads to dU=C_{V}dT so \color{red}\left(\frac {\partial U}{\partial V}\right)_T = 0 meaning that internal energy of NONideal gas is a sole function of T? 2. As...

Homework Statement Water at the top of Niagara Falls has a temperature of 10.0degrees celsius. If it falls a distance of 50.0m and all of its potential energy goes into heating the water, calculate the temperature of the water at the bottom of the falls. Homework Equations W = change...

Homework Statement You are given a device with which to operate with an input resistance of 50 W. The device requires 9 V to operate. However, the only available power supply is a 12 V source. Part A:Using only resistors, design an interface circuit to lower the 12 V to 9 V for operating...

I'm here to discuss motion in spacetime and how it works to hopefully get a better understanding of it. Specifically "spacetime swimming", and the motion of a "relativistic glider", which is talked about in this article "Surprises from General Relativity: "Swimming" in Spacetime" By Eduardo...

Consider the following situation. Two particles are initially separated by some distance and are then pulled further apart, thus increasing the potential energy of the system (due to the gravitational force of attraction between them). If I am correct in understanding special relativity, then...

http://img689.imageshack.us/img689/511/pistonquerstion.jpg This is my part attempt... [PLAIN][PLAIN]http://img830.imageshack.us/img830/7342/internalenergyanswer.jpg And ideas on how I can do the rest of it?

I would like to know if there is change of phase during total internal reflection. (In particular I would like to know if I can cover copper with several microns of glass and have it reflect 200 MHz EM waves coming from water (epsilon(H2O)=80, epsilon(glass)=4)).

A mixture of red and violet light is incident on a glass-air interface. The indices of refraction for red and violet light in glass are n(red)=1.52 and n(violet)=1.538. What color of light enters the air? http://www.webassign.net/cj8/q_10.gif attempt to solve: I found that the critical angle...

Homework Statement http://img408.imageshack.us/img408/6537/screenshot20100808at134.png Homework Equations The Attempt at a Solution I redrew the circuit as follow: http://img293.imageshack.us/img293/6247/screenshot20100808at135.png Is this correct (or even useful in the first place)...

Suppose a (uniform) chimney began falling. Where would the chimney break? I approached the problem by considering the torque acting on a point along the chimney, at a distance x from the point of rotation. I got the internal torque + external torque = (mx^2)(3gcosA/2L), where A is the angle...

What are some of the major (if not the major) difference(s) between the inside of a single specialized cell (like a muscle cell or a skin cell) and a single-celled organism. Does a single-celled organism have the capacity to make more "decisions" than a muscle cell?

Hello! First post here :-) Hope this isn't too simple for this forum...if so, by all means give me a pointer... I'm wondering about some basic thermod. concepts. Could somebody please shed a little light on these? Internal Energy and Enthalpy (both from macroscopic viewpoint) Does...

Hi all, first to say sorry if the question is repeated second time I've order a couple of internal gears from Rollix as picture below: http://img155.imageshack.us/img155/5996/centerdistance2.jpg The calculation from them for internal gears with center distance C=331.494 (mm) Backslash at...

Please can someone explain clearly in perhaps lay man terms the difference between REVERSIBLE & NON REVERSIBLE INTERNAL COMBUSTION ENGINES. Thanks

http://www.cdeep.iitb.ac.in/nptel/Mechanical/Heat%20and%20Mass%20Transfer/Conduction/Module%202/main/2.6.3.html" Kindly see the above link I will be placing a temperature sensor in the hollow area and insulate the outer surface(with let's say Plaster of paris)...I will place a fire...