Frequencies Definition and 395 Threads

Homework Statement An object producing a sound with frequency 500 Hz is traveling at 40 m/s toward an observer, and the observer is traveling at 30 m/s away from the source. Another source producing a sound with the same frequency is traveling at 10 m/s toward a stationary observer...

Homework Statement Ultrasound pulses of with a frequency of 1.000 MHz are transmitted into water, where the speed of sound is 1500m/s . The spatial length of each pulse is 12 mm. a) How many complete cycles are in each pulse? b) What is the lower bound of the range of frequencies must be...

Homework Statement A guitar string is 90.0 cm long and has a mass of 3.17 g. From the bridge to the support post is 60.0 cm and the string is under a tension of 506 N. What are the frequencies of the fundamental and first two overtones? (f1,f2,f3) Homework Equations v=sqrt(FT/m/l)...

I need help on question 2 and 3. For question 2, I think I got the expectation for Poisson distribution, but I have no idea how to get the normal one. Could someone provide me a formula or something? Thanks a lot!

Homework Statement http://www.aijaa.com/img/b/00322/3721717.jpg http://www.aijaa.com/img/b/00092/3721734.jpg Both supplies are basic sine waves and the frequency of the supply 2 is 100Hz. The assignment is to calculate the power that is transformed to heat (i.e the power the resistor is...

When I see a graph of a Fourier Transform, or something in the frequency domain, say band-limited from -\Omega to \Omega, I'm confused to what the interpretation is of the negative frequencies. Physically it would seem as though something considered in cycles/second for example, should be...

Homework Statement A loudspeaker at the origin emits sound waves on a day when the speed of sound is 340 m/s. A crest of the wave simultaneously passes listeners at the (x, y) coordinates (40m, 0) and (0, 30m). What are the lowest two possible frequencies of the sound? Homework Equations...

So I did a little search and I can't seem to find any threads regarding amateur radio. Is anyone a ham out there and what frequencies do you lurk at and where? I'm a new ham, don't know why I decided to get into it but timing seems to be about right with new radios like Yaesu VX-8R and many...

A book is placed on a horizontal wooden plane that is undergoing simple harmonic motion with an amplitude of 1.0 m. The coefficiet of friction btween the book and the horizontal wooden plane is given by μ = 0.5. Determine the frequebcy of the horizontal wooden platform when the book is about...

Homework Statement i have values of input signal frequencies and relevant voltage gains(Av) of a amplifire.and i want to find upper and lower cutoff frequencies by drawing a graph.can someone tell me how to find upper and lower cutoff frequencies with following values. thanks here is...

hi,im a newbie over here,my physics quite poor so i really need help by understanding it,i jz wanted to ask could any1 please explain to me what is in phase,&out of phase?;im totally baffled.:blushingAnd what's frequencies of the normal mode in standing waves in a string fixed in both ends?i...

i want to listen to radio on my mobile without earphone. so i need a very good wave absorbing material in d stereo jack. please suggest me some good metal that i can use as antenna.

Homework Statement The fundamental frequency of an open organ pipe corresponds to E above middle C (329.6 Hz on the chromatic musical scale). The third resonance of a different closed organ pipe has the same frequency. What are the lengths of the two pipes?Homework Equations natural frequency...

What is the smallest electromagnetic frequency and the largest possible electromagnetic frequency? Also, can small frequencies ride on larger frequencies? Ergo. You are traveling 99.7 the speed of light away from something shooting a blue light light at you. What frequency is it? Once it...

Homework Statement Hi! I have been given such a task: A population of firms can assume three states: good-bad-bankrupt (default) The cumulated frequencies of default (DP) from year 1 to 10 are given. Find an appropriate transition matrix (TM) I'm given a matrix of historical cumulated...

A microphone is located on the line connecting two speakers that are 0.650m apart and oscillating in phase. The microphone is 2.25m from the midpoint of the two speakers. What are the lowest two frequencies that produce an interference maximum at the microphone's location? okay, so i have...

Take a two sound waves: for example let us spread them at both poles of the human hearing spectrum. The low frequency at 20Hz and the high at 20,000Hz. Which sound wave carries with it more energy? It is said that sound travels at 343m/s, is that true of all sound in the air medium...

Ok I seem to have a serious problem. My understanding of Bandwidth was that it is the Range of Frequencies that a Radio Receiver can let through its RLC Circuit (or known as the Bandpass Filter). I thought that The set of frequencies are such that they are larger than half the total power...

Hi all, I am new to the forum and am despreate for the solution for my current task. I am given a canteliver beam with the dimention: L =1250mm W= 75mm D= 30mm E=200 Gpa density = 7800kg/m^3 poison ratio=0.3 and I optained the first five natural frequencies from COSMOSWorks 2007...

I was just thinking the other day about how they triangulate on radio frequencies. Imagine an illegal fm broadcast they are trying to find. From thought (not necessarily right), they would have 3 vehicles with receivers that would form a triangle and depending on angles and the time it takes...

How are the orbital frequencies of single atomic electrons, and covalent electrons determined?

Homework Statement What are the wavelengths in air of the lowest and highest audible frequencies if te range of human hearing is 20 Hz to 20 kHz and the sped of sound is 342 m/s? Homework Equations v= \lambdaf The Attempt at a Solution v= \lambdaf 342 = 20 Hz \lambda \lambda = 17.1...

(1) My requirement for this project was to build an instrument that can produce all the notes in a C scale. The accuracy of the notes is to be judged through Frequency (Hertz). I decided to build an instrument whose design is comprised of eight electrical conduit tubes (metal) that are about...

Homework Statement I need to solve the following wave equation: [\nabla^2 + \frac{\omega_a^2}{c^2}\epsilon]\mathbf{E_a} = -\frac{4\pi\omega_a^2}{c^2}\mathbf{P}^{(3)} Homework Equations \mathbf{P}^{(3)}=\chi^{(3)}:\mathbf{E_1E_1E_2^*} E_1 and E_2 are two electric fields with...

I know how beat frequencies work with sound. I know they exist in RF so how do they affect light?

My first post... I'm studying physics at school (9th grade) and learned that light has lots of different frequencies above/below visible spectrum. I also know that the speed of light is a constant (300Kps). My question is, does light (all frequencies) travel together like one multilayered...

I'm working on some physics problems involving sound frequencies with string and wind instruments, and the current problem has the temperature drop from 20deg Celsius, to -12.7deg Celsius. Too my knowledge this problem disregards any wood expanding/contracting done by the instrument by the...

Here's an interesting problem that might be best solved by physics: Lets say your neighbors insist on using a loud subwoolfer late at night, it travels through your appartment walls and keeps you up all night. What would be a good way to cancel out the noise, other than earphones?

At a time when pc's come with microprocessors clocked at frequencies of the order of 4 GHz, it must be possible to drive a D/A converter at microwave frequencies. Anyone know of hardware to do this? Anyone know of suitable hardware to transmit the waveform at a power density comparable...

Homework Statement Express the given sinusoid in terms of exponentials and determine the complex frequency(s). 4(e^-2)cos(wt + pi/4) Homework Equations Euler's identity: A(e^i*theta) = A[cos(theta) + i*sin(theta)] The Attempt at a Solution I'm really drawing a blank here...

If one reads the current version of the wikipedia entry on Photoelectric_effect we see that historically the postulate E=h f predates the relativistic theory. So it is kind of circular to argue in terms of E=h \nu to justify E=h f. The empirical process first postulated E=h f for the black...

How To Fing Angular and Natural Frequencies WITH ANSYS ?? [FONT="Arial"]Good Day every body, I am student in Ruhr Universität Bochum and I would like to ask please about the procedure how to find Natural and angular frequencies for a simple beam to get the idea fro it and to solve my proble...

Homework Statement If there are three frequencies: 200hz, 206hz and 209hz, how do you calculate the beat frequency of three frequencies? Homework Equations Fb=abs(F1-F2) The Attempt at a Solution

could you find the planks formulas transformation for high and low frequencies please.

Need urgent help, beat frequencies and tuning. Homework Statement http://img144.imageshack.us/img144/4337/2aee8.th.jpg Homework Equations The Attempt at a Solution You can see my attempt in the picture. I assume that beat frequencies are the absolute value of the difference...

Homework Statement The problem asks to determine the break frequency at the base of Q2 (which is fine I have no problem with that), but the whole assignment never asks for the break frequency at the COLLECTOR of Q1, then later asks to produce a bode plot of the transfer function. See the image...

Homework Statement I need to figure out the normal frequencies (or eigenfrequencies) of a system of two simple pendula (call them A and B), connected with by a massless rigid rod at an arbitrary distance from the pivot point or the mass. That is, the pendula are not connected at their masses...

Hello good members and guests of PhysicsForums. Whats the deal with this? Are we going to be fueling vehicles with sea water now? http://green.yahoo.com/index.php?q=node/1570

i know you've heard this in a movie or something, usually when a ship is sinking or the last survivor of the human race is looking for other survivors. considering a transmitter is just a driven LRC circuit oscillating at a certain frequency, is this possible? obviously you could have a bunch of...

hey how come the IR heat up materials more than UV ? and why people say IR go longer distances the way i see it : UV have faster frequencies, they should have more energy while IR have slower frequencies, should have less energy or is it that when hitting a electron , photons that...

Can someone elaborate on the relationship of the Riemann zeros and primes? How are the zeros harmonic to the primes? The quotes below mention the 'sum of its complex zeros' and 'other sums over prime numbers'. Can someone clarify this? From Answers.com: "The zeros of the Riemann...

hey i am wondering, what's the equation to find the result equivalent frequence of a mixture of two other different light frequences in same proportions ? (like if u have one red torch , and one blue torch , and u aim the light of each on the same zone) or is the result color not...

Fundamental frequencies Using the formula Would it be correct to say that to determine the necessary tension for the fundamental frequency at 60hz, substitute into the equation f, m, and L, then solve for T?

Homework Statement Two equal masses are connected by two massless springs of constant k and nat. length l. The masses are constrained by a frictionless tube on a pivot, (also massless) so that they remain colinear with the pivot. The pivot subtends angle theta with the vertical. The 1st mass...

-Look up or derive the frequencies of the standing waves of a length of wire, L, clamped at the ends and under tension. -What are the similarities and differences between a vibrating string and a resonating pipe? -Does the diameter of the wire matter? -Does the diameter of the pipe matter...

Maybe the wrong word but can you get electromagnetic radiation in any frequency or is there a "quantum" frequency for which all other frequencies are some integer multiple? Related question - is there an absolute low and high frequency?

It is known that any non-sinusoidal wave can be regarded as a combination of sinusoidal waves of different frecuencies, with the ‘weight’ of the different frecuencies given by the function called Fourier transform. On the other hand, if we have an electromagnetic wave, we know that it is the...

Hello, I need to know the fundamental frequencies of the noble metals "silver, gold, platinum ... etc" .. thank you very much

Homework Statement The frequency of the note f_4 is f_F. If an organ pipe is open at one end and closed at the other, what length must it have for its fundamental mode to produce this note at a temperature of T? ans= v/(4*f_F), where v is the speed of sound in air. Now the part which...

"Combining high frequencies to get a large frequency" "Combining high frequencies to get a large wavelength" Is this possible? There will be constructive and destructive interference, but can there be anything that increases the wavelength?