Internal Definition and 993 Threads

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 "From your graph, calculate the EMF and internal resistance of your cells. Include uncertainties in your calculations" Now I know how to work out the emf and int. resistance, but I am just not sure about how to incorporate uncertainties. Homework Equations y = mx +...

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...

Can you help me with this problem? An ideal gas is compressed adiabatically. The work done over it is 200 J. How much will the internal energy change? A) 200 J B) 100 J C) -200 J D) 0 J Which formula do you use to solve it? Thanks in advance!

1. A gas bottle with a volume of 0.1 m3 contains 0.4 kg of a gas at a pressure of 7 MN/m2 and a temperature of 150 ºC. For this gas Cp = 10.54 kJ/kg K. Calculate the changes in internal energy when temperature is raised to 500K Given answer: 362 kJ 2. pV=mRT pv=RT...

Just had a thermodynamics exam, and one of the questions was For an ideal gas, is the relation \DeltaU = mC_{}v\DeltaT restricted to constant volume processes only? Why? I wrote that it was only valid for constant volume processes, because this is what C_{}V is defined as, however now I'm...

Hello all, I am confused with naming of the Zeeman effect (in nuclear or/and electronic levels). Is that means: 1. splitting of spectral lines due to internal magnetic field, or 2. splitting of spectral lines due to external magnetic field, or 3. splitting of spectral lines due to...

I'm working from Feynman's definition of internal energy for the Debye theory of heat capacity. I'm trying to use that to derive the normal definition of heat capacity that I've seen. But I'm running into a problem. Note, in the following V_0 is frequency, whereas V is volume (that's how Feynman...

What's the difference between enthalpy and internal energy? Internal energy is the average of the kinetic energy (linear and angular) of the particles of the body (or system), right? Could someone explain me this clearly? Thank you

Homework Statement A 15.0 kg block is sliding across the floor. Initially, it is moving at 1.2 m/s. However, after sliding 20.0 meters, =7.5 J of work are done on it by friction. What is the block's velocity after sliding 20.0 meters? Homework Equations KE=.5v2 lw-l=F\DeltaXcos\theta...

Homework Statement A plane wave is incident at 70˚ to surface normal traveling within a medium with relative permittivity = 4, striking the boundary with air. Where is the nearest magnetic field max. to the boundary in the initial medium? Find the 1/e penetration depth of the evanescent...

Just like the title, does battery capacity depend on internal resistance? I know it does depend on the temperature and the chemical structure of the battery, but does it also depend on internal resistance? If so, how dependent are batteries on internal resistance? Also, what is the...

Homework Statement Prove that D4 (Dihedral group) cannot be expressed as an internal direct product of two proper subgroups. Homework Equations The Attempt at a Solution I know that the only two possible subgroups would be the subgroups of order 4 and 2. I am thinking since D4 is...

Homework Statement What is the maximum value of θ1 that would cause total internal reflection to occur? N1 = 1.3, n2 = 1.6 (picture attached) Homework Equations Critical angle = sin^-1(n1/n2) The Attempt at a Solution I figured the critical angle to be 54.3. That means that...

I'm currently doing a project on neural network controller for an internal combustion engine to reduce emissions level. Can anyone assist me in training such models (neural networks)

if you're given just the temperature and internal energy of R134A how do you determine the phase of the substance? If I was given the pressure instead of internal energy then i would just look in my tables to see if the pressure is above or below the saturated pressure and i would then know...

Homework Statement Let H and K be groups and let G = H x K. Recall that both H and K appear as subgroups of G in a natural way. Show that these subgroups H (actually H x {e}) and K (actually {e} x K) have the following properties: a: every element of G is of the form hk for some h in H and k...

Hi guys. I am working on making a haptic device for a baseball simulator. Now the problem is that I want to replace the external force for the ball hitting the bat with an internal force in my bat-like device using either solenoids or motors. Do you think it is possible to replace the external...

What is the relationship between viscosity and convection in the mantle?

Question about internal energies... PLEASE HELP ME! What must be true for two objects of the same material to have the same internal energies? (Choose all that apply) a. The masses of both objects must be equal b. Both objects must have the same density c. The temperatures of both...

I have an issue I'm not quite sure how to approach. A customer is requesting that we prove that our battery pack chassis will not burst or deform if additional gases are introduced inside the enclosed box (the batteries could vent). The chassis is assumed to be a sealed .05" thick 5052 AL...

Homework Statement Use your program for the viscously damped spring to solve this problem. Make sure you change the parameters as specified below. A mass m=7.1 kg is attached to the end of a spring with a spring constant of k=16.4 N/m. The mass moves through a viscous damping medium with...

Homework Statement I have two identical volumes of gas, and I heat them both to 100 C, one under constant pressure, one under constant volume. Which has more internal energy after the process? The attempt at a solution I believe that they both have the same as the extra heat you have...

the queen posted truss in the picture consists of the beam ABCD, compression members BE CF amd the cable AEFD, a stress analysis under the uniform load q is required. outline an analysis procedure, state the effects you would ignore and why. i am not sure what i am meant to be doing here...

Okay, so I've found this site (http://www.spiritofmaat.com/archive/feb2/carplans_doc.htm) and it claims to have a reliable method to convert a diesel engine to run off of hydrogen. Now, my question is is this actually feasible in the method they've described? I've asked two other sources and so...

There are a couple of products on the market which allow you to attach an external desktop gpu to the laptop and then use an external monitor and play games using the the desktop gpu instead of the weaker gpu in the laptop. It's a great idea but it means that you must carry an external...

Homework Statement A car of mass 2200 kg collides with a truck of mass 4500 kg, and just after the collision the car and truck slide along, stuck together, with no rotation. The car's velocity just before the collision was < 35, 0, 0 > m/s, and the truck's velocity just before the collision...

Homework Statement There's .1 mole of an ideal gas trapped in a cylinder with a movable piston. If Pi= Pf= 5000Pa, Vi= .04 m^3, Vf= .08m^3, Q=500J,,,Find W, change in (U), Ti and Tf. Homework Equations change in U = Q+W W= -p change in V The Attempt at a Solution W= 200J...

Is the internal resistance of the battery or other source is variable or not? without discharging . Is it depend upon on the external resistance?

Homework Statement 2 moles of a monatomic ideal gas expands from state A to state B. PA = PB = 600 N/m2, VA = 3.0 m3 and VB = 9.0 m3. i. Calculate the work done by the gas as it expands. ii. Calculate the change in internal energy of the gas as it expands. iii. Calculate the heat added to or...

Homework Statement does a flashlight battery have an internal resistance? explain. this problem is for my lab, and we are farther ahead in lab than in lecture. so i haven't actually learned this material yet. Homework Equations i'm not really sure. R=∆V/I also, -VB + VR + VM +...