Conceptual Definition and 874 Threads

Hello, Why does electromagnetic wave intensity attenuate exponentially with depth from its incident intensity in an object? Why is the relationship exponential? I just need a nudge in the right direction or more if you are willing. Thank you for any help!

If a sphere is moving through air. Will it have more drag if it is spinning while moving or just moving ?

Let's say I wanted to calculate the distance between the Earth and the Moon (assuming that the system in question only includes the Earth and Moon, the Earth remains stationary**, and the Moon undergoes a circular orbit around the Earth and thus acts as a satellite). The relevant equation is: r...

When a broadband 800nm sub-ps pulse propagates through ZnTe parallel to the {110} plane it produces in-phase THz radiation by moving the electrons down either the [-111] or [1-11] axis. Due to the electronegativity of Zn and Te the electric field of the optical pulse will push electrons...

My question is can someone just check my reasoning to make sure I am understand what is happening. There is a block on a spring in SHM and it has an initial energy E that is given by stretching string. What would happen to the system if you increase the mass by 4 and you repeat the...

If you look at the diagram right below the headline "Electric potential diagrams" in http://www.physicsclassroom.com/Class/circuits/u9l1c.cfm" (about halfway down), you can see that in circuit A, the electric potential at point A is the same as that at point B, and likewise for points C and D...

Ah. I get it. Yes, well, it spread to PF, so... The standard definition of Conceptual Art back in the day was: art in which the concept of an artwork was, itself, the artwork. This was a subset of Modern Art, one weird branch of it. One of the best known conceptual artists was a...

In chapter 4 of A First Course in General Relativity, Bernard Schutz introduces the idea of a fluid element, a different one assigned to each point in a fluid. When he talks, in section 4.5, about the 3-volume of a fluid element, is this 3-volume defined with respect to the MCRF (Momentarily...

I was wondering about the first law of thermodynamics and isothemic expansion. Is there an increase in the the total internal energy of a gas through this process. If not is there a way to calculate heat (i can calculate work) through this process as both pressure and volume vary. Also is an...

Hi there. Here is the deal, today morning in my thermodynamic class we were making some exercises of stability, and then surged a question about internal energy. The thing is I thought that the internal energy should be always positive in sign. This doesn't mean that the variation must be...

Homework Statement A golf ball is hit so that it leaves the ground at 60° above the horizontal and feels no air resistance as it travels. Which of the following statements about the subsequent motion of this ball while it is in the air is true? a. Its acceleration is zero at its highest...

I have some concept problems that I cannot seem to master. I have them narrowed down to what I think the answers are but I keep getting them wrong. I'm supposed to choose all the statements that are false. A motorcycle moved along a straight road at a constant speed. The magnitude of its...

I have some concept problems that I cannot seem to master. I have them narrowed down to what I think the answers are but I keep getting them wrong. I'm supposed to choose all the statements that are false. A motorcycle moved along a straight road at a constant speed. The magnitude of its...

Homework Statement A sailboat is traveling east at 5.0 m/s. A sudden gust of wind gives the boat an acceleration a =(0.80 m/s^2 and 40 degrees north of east). Homework Equations V = Vo + at X - Xo = Vo*t + .5at^2 V^2 = Vo^2 + 2a(X - Xo) The Attempt at a Solution I...

This isn't a homework question but something I thought up but couldn't figure out. If I tie a block to a rope at a very high elevation and throw the block down, what would the force-time diagram look like (from the moment the block is thrown) until the block begins to oscillate and how would...

I think I know the answers to the question I am going to ask but I am just going to make sure. This is going to be quite simple for most of the experts here so here goes: If we have a parallel plate capacitor and we double the distance between the plates while keeping the charge Q on the...

Homework Statement A friend and I were arguing about how tension created by a submerged ball affects the total weight of the container. Homework Equations I couldn't find anything similar to the situation, so I drew a quick picture to better illustrate the situation :D A string is...

Hey guys, so I have a homework question that I have already solved one way, but when I try it another way I can't seem to get the correct answer. First of all, the question is: "A single resistor is wired to a battery as shown in the diagram...

Yes, yes I know about the template, but these questions are so basic that I don't really know what I can show as work... Sometimes all I need for help is the relevant equation itself -.- So please don't delete or hate. Thanks! 2. http://tinyimage.net/images/50136173150204648365.png The...

Suppose you have a can (like a spray can) in a vacuum. You poke a hole in the can and the pressure from the can pushes it to the right. Now suppose you have a vacuumed can within a pressurized container and then you poke a hole in it. Which way (if at all) does it move? I know this is sort of...

Suppose you have a can (like a spray can) in a vacuum. You poke a hole in the can and the pressure from the can pushes it to the right. Now suppose you have a vacuumed can within a pressurized container and then you poke a hole in it. Which way (if at all) does it move? I know this is sort of...

Okay, so I am somewhat new to physics (finishing up my first Mechanics/EM course), and I often get stuck on concepts until they make sense to me intuitively. Everything to do with translational motion made sense instantaneously, and I have powered through EM, but I have always struggled with...

Hello! I have essentially no knowledge of quantum physics, these are just questions that popped up in my mind today. I'm new to these forums, so I posted here as the quantum physics forum might be a platform for more advanced problems. First of all, what happens to the photons, when an...

Just a very conceptual question about measuring momentum of a particle: first off, when we measure the position of a particles by say, firing a photon at it, its wave function collapses to a spike at the point where the particles was seen.. If we measure the momentum of a particle, its wave...

Homework Statement I am just wondering, can the voltage in a capacitor ever be equal to or greater than the voltage in the power supply? Probably not the power supply...but is it possible to be equal to? The Attempt at a Solution

Hi, Originally I had a question about a wire that allows electrons to move to higher voltage. I could not figure out why the wire does not lose electrons to the point it runs out. The question was answered on these forums when someone mentioned salt bridges, which lead me to watch some video...

"conceptual" electronics book Hello, :wink: I have seen some books which do not explain give any conceptual background to electronics concepts. They use math to explain everything. I am in search of a book which first explains the concepts from conceptual point of view then comes to simple...

When you sit in the passenger seat, why do you feel pushed up when you make a left turn? Explain using Newton's laws of motion.My Guess: Newtons third law states there is a reaction for every action. So when you turn left the opposite reaction would be you turning right? IDK LOL :|

Hello all, I just came across a problem that I had previously solved. A relatively simple one. What I do not understand though is why I can use the equation that I have used so many times in this particular situation. Here it is: Homework Statement A baseball pitcher throws a baseball...

Homework Statement The spectrum of a hypothetical atom is shown in the figure. Three distinct spectral series are shown, with the center series corresponding to transitions to a final state of n_f = 3. (f is final) The indicated spectral line corresponds to the transition from an initial state...

according to wave particle duality particles such as electrons exhibit wave like properties. and the wavelngth is given by lambda=h/p, so increase momentum and get shorter lambda. This property is utilised in the electron microscope to get very short wavelengths and so have very high...

Listed below are just a things I cannot figure out involving rotational motion (one involves a situation). -Why does Kinetic Friction do no work if bodies roll without slipping? I thought it would add torque to provide more energy for rotational motion. Situation: A solid bowling ball...

according to wave particle duality particles such as electrons exhibit wave like properties. and the wavelngth is given by lambda=h/p, so increase momentum and get shorter lambda. This property is utilised in the electron microscope to get very short wavelengths and so have very high...

1. Homework Statement A) A current loop is placed in a uniform magnetic field that is directed out of the page as shown. The current is clockwise as shown. What, if anything, happens to the loop? B) Consider the following rigid coil that is placed in a uniform magnetic field that is...

Okay so I know that when a wave moves from a medium to a different medium that it changes in the direction if the speed cahnges. So when a wave moves slower it moves towards the normal. However, I have a lab question that says, "A small particle will have to speed up, in the direction...

Two concepts whose definitions are unclear to me: 1) Provide a fundamental operational definition for work done. From this definition, prove or provide a link or explain the work-kinetic energy theorem. 2) Provide a fundamental operational definition for the center of mass of a system of...

Homework Statement A window washer of mass M is sitting on a platform suspended by a system of cables and pulleys as shown . He is pulling on the cable with a force of magnitude F. The cables and pulleys are ideal (massless and frictionless), and the platform has negligible mass...

Explain why the Compton effect provides critical evidence for the particle model of light. I know the Compton effect proved that light has momentum but not sure how that is evidence for particle model of light. Can someone help?

1)So I will describe my lab situation first, then ask my main questions. In my physics class we had an inclined air track, with 5 masses (carts) and 5 springs connected in between them. We turn on the air track to replicate a mostly 'frictionless' surface. Now we did several trials writing...

I was doing some problems out of my book and the following problem has been solved, but a little question popped up in my head. Its simply conceptual, just want to gain a deeper and truer understanding of these two fundamental ideas... The problem goes something like this...(easy...

Homework Statement I just want to know why the tension in the rope in system A is not equal to 100 lbs, while the tension in the rope in system B IS 100 lbs. [PLAIN]http://img823.imageshack.us/img823/9462/conceptualquestion.png In system A, a 100-lb mass is hanging. In system B, there...

Homework Statement You are standing on the sidewalk, looking toward a shop window. You notice the reflection of a person of your height walking toward you. The reflected light is partially polarized. Is it polarized vertically, horizontally, or somewhere in between? Homework Equations...

Homework Statement I have a rather conceptual question, if I can understand it I can probably solve the prblem. Here is the problem: me and my equipment weight is w N. I am climbing a mountain and I climb an elavation of h meters. Now, my body convert 25% of energy burnt from fat...

Homework Statement An air bubble rises in water and makes contact with a container wall. Does contact with the solid surface change the bubble volume even if the surface is neither hydrophilic nor hydrophobic, but forms a contact angle of 90 degrees with the air-water interface?(Neglect...

So I'm pretty sure I have the right answer I just want to make sure I am getting the idea. There is a large solid copper cube. At the center of the cube there is a hollow sphere of radius a. At the center of the hollow sphere there is a charge Q. What is the total charge induced on the...

Homework Statement An electric dipole antenna used to transmit radio waves is oriented vertically. At a point due north of the transmitter, how should a second electric dipole antenna be oriented to serve as a receiver? answer=vertical (since it should be aligned with the electric field...

Homework Statement Let A = matrix of size m x n, where m can or cannot be equal to n. The matrix is Rref(A) is in a "perfect staircase" in which exists a unique solution. What can you comment about the Span of the column and row of this matrix? The Attempt at a Solution I am...

Hi - I'm trying to work out the following convolution problem: I have the following integral: \int^{\infty}_{-\infty}p(x)U(x)e^{-i \omega x}dx Where p(x) is any real function which is always positive and U(x) is the step function Obviously this can easily be solved using the...

Hello everybody, I am having a hard time understanding a very simple principle involving a rolling wheel. I know that the velocity at the bottom "contact point" of a rolling wheel is zero relative to a stationary observer.. yet I don't see how this is true. So I made a quick sketch and here is...

Homework Statement Lets say a wire has Youngs modulus Y, Initial length L area A and is supporting some external load/force of magnitude F...its extension is dl..We say that the Potential energy of wire is 1/2(YA/L)(dl2)...But i am having a problen with the energy changes... Homework...