Frequencies Definition and 412 Threads

Hi everyone, So, resonance, are resonant frequencies and natural frequencies the same thing with a different name? If not could someone please explain the difference. Been searching for the answer for over an hour. Thanks in advance Peter

I am a piano teacher with some very cool, science-minded students. Usually we stick to basic acoustics, and mechanics in terms of piano technique, but yesterday one of them took things in an interesting new direction. . . he described to me how, when he closes his eyes and listens to the music...

Homework Statement Two strings have different lengths (L1 = 3.920 m and L2 = 1.960 m) and linear densities (mL1 = 2.64E-1 kg/m and mL2 = 6.60E-2 kg/m), as the drawing below shows. |........| |........| |----------------------------------| |........| |........| (Okay, only the "-"s...

Assuming a flat pane of colored glass, using colored lights... If you pass red light through red glass, will it be blocked? How about if you pass red light through a green glass- What will the color/frequency of the light which passes through the glass be? Would you simply add the frequency...

If I am correct, crystal frequencies depend on the size, shape/cut, and purity of a crystal(?) How can you measure (what instrumentation) the frequency/ies of a natural crystal (other than just quartz)?

Hi Say I have a real quantity given by x(t) = \int_{ - \infty }^\infty {\tilde x(\omega )e^{ - i\omega t} d\omega } Now I complex conjugate it (remember it is real) x(t) = \int_{ - \infty }^\infty {\tilde x^* (\omega )e^{ + i\omega t} d\omega } How is it that I from...

I am having problems understanding the "systematic method" for determining the frequencies and amplitude ratios of normal modes when a system has more than one degree of freedom. I think I initially have problems setting up the differential equation that describes the motion. Here is the...

Homework Statement A guitar string is 90.0 cm long and has a mass of 3.16 g. From the bridge to the support post is 60.0 cm and the string is under a tension of 520 N. What are the frequencies of the fundamental and first two overtones? L_s = 90.0 cm = .9 m L_bsp = 60.0 cm = .6 m m = 3.16 g =...

Homework Statement 1)A stretched wire vibrates in its first normal mode at a frequency of 383 Hz. What would be the fundamental frequency if the wire were one fourth as long, its diameter were quadrupled, and its tension were increased four-fold? 2)A 0.0125 kg, 1.88 m long wire is fixed at...

Hi, I am wondering what sort of frequencies electrons have in atoms at different energy levels. When I say frequency, I'm *not* talking about the frequency of the orbiting motion. I am wondering what the electron wave oscillation frequencies are at the different energy levels. A couple...

Hi In (quantum) optics, many authors state that the field amplitudes satisfy E\left( { - \omega } \right) = E^* \left( \omega \right) But how is it that one can prove that this is correct? I have never seen any book do this,

For an assignment (not really homework, but not really exciting either), I'm trying to calculate the total entropy for the reaction: Na2 + X2 \rightarrow 2 NaX Where X = F, Cl, and Br . ( I told you this isn't exciting). Also, in this theoretical reaction, everything involved is an...

Hi Could someone kindly clarify the following? Homework Statement In its ground state the atom absorbs 2.3 × 10–19J of energy from a collision with an electron. (i) Calculate all the possible frequencies of radiation that the atom may subsequently emit. Homework Equations E=hf...

Hello everybody, I have a question about the undamped natural frequencies for a three degree of freedom system. The equation of motion for the undamped system is : M\ddot{x}+K\dot{x}=0 The undamped natural frequencies I found is a complex number ...

Homework Statement Hey. I am new here. Recently i got a C assignment (computing) in which i was given around 20 files..each with thousands of AC voltage test samples sampled at 1 ms..so technically 100 samples= 1 second. I was told that there 3 different kinds of frequencies in the files and...

I am doing a small physics research project introducing sound, resonance, and natural resonance frequencies, but I have questions. I know that resonance is the tendency of a system to oscillate with larger amplitudes at some frequencies rather than others. Does this just mean that the...

For example, why is it that sand stays hot even after the sun goes out, stopping the source that excites its electrons, shouldn't that make it immediately cold, or is the radiation released in a shorter amount of time, and if so how?

Homework Statement musical notes are defined by the frequency of oscillation. however notes are usually not qualifies in terms of absolute frequency, but the ratio (called interval) of their frequency to that of a reference notes called root. Pythagorus discovered that intervals that please...

Homework Statement Find the frequency of combined motion of the following (a) x = sin (12pi.t) + cos(13pi.t + pi/4) (b) x = sin(3t) - cos(pi.t) Homework Equations The book I'm using states that if the periods are commensurable ie if there exist 2 integers n1 and n2 such that n1T1 =...

I was reading today about de Broglie and I don't think I really get what is meant by particles having a wave frequency. What is being measured as a wave, the oscillation of the electrons? Also, the book said something about the electrons sending out waves that move faster and even catch up...

Reading some QFT in which we are faced with inhomogeneous equation (\partial^\mu \partial_\mu + m^2)\phi(x)=J(x) The solution is given as \phi(x)=\phi^{(+)}_{in}(x)+\phi^{(-)}_{out}(x)+i\int{d^4 x\Delta(x-x')J(x') where \Delta is the appropriate Green's function. "in" means the...

The PCI bus found in many computers transmits 64 bits per clock cycle at 33MHz. How does the bandwidth of the PCI bus compare to the serial FireWire (IEEE 1394) serial bus specification, which is 400 Mbits per second? a. The FireWire serial bus is better. b. The PCI bus is better. c. They...

Hi I was wondering if someone would be kind enough to help me with a project I have at the moment. Here is the scenario; I am playing various tones through a speaker system at a fridge and I need to be able to detect which of the tones make the fridge resonate. I have been using a...

Hy. I want to find a lot of info about the moon. I've read about gravity. I want to know about the frequencies, radiations and whatever there is, and how them interact with earth. Where should i search? Thanks!

Why does a wave go up and down? What forces cause waves to go up and down? In order for a particle to be a specific frequency would depend on what?

A violin string has a length of 0.350 m and is tuned to concert G, with fG = 392 Hz. Where must the violinist place her finger to play concert A, with fA = 420 Hz? If this position is to remain correct to half the width of a finger (that is, to within 0.600 cm), what is the maximum...

So I've been reading up on optical rectennas, and the sources I read say that the reason such devices are not yet efficient enough to be practical isn't the antenna, it's the rectifier, since solid-state Schottky diodes of the types normally used don't work in the THz range of AC frequencies...

Homework Statement x(t) = 3*sin(1000*pi*t) Suppose that the signal is sampled at a rate of fs = 2000Hz. What is the discrete time signal obtained after sampling (i.e., the signal expressed as a function of sample number n, x[n]) What discrete time frequency, f-hat will the signal x[n]...

I'm wondering if gravitational waves can have a wide range of frequencies and wavelengths much like EM waves, or if they are more uniform and only vary in amplitude. Also, should gravitational waves experience a Doppler shift?

Homework Statement Two strings on a musical instrument are tuned to play at 262 Hz (C) and 294 Hz (D). Questions: 1. If the two strings have the same length and are under the same tension, what must be the ratio of their masses (MC/MD)? 2. If the strings, instead, have the same mass...

Homework Statement The mass of the deuterium molecule D2 is twice that of the hydrogen molecule H2. If the vibrational frequency of H2 is 1.22 × 1014 Hz, what is the vibrational frequency of D2, assuming that the “spring constant” of attracting forces is the same for the two species? Answer...

Homework Statement The question is a 2 D.O.F system, m1 = 600kg, m2 = 50kg, k1 = k3 = 0.5MN/m, k2 = 0.2 MN/m. Calculate the natural frequencies. Homework Equations 1167-w^2 -333.3 X1 0 = -4000 14000-w^2 X2...

I'm trying to figure out how to build a breadboard instrument using either push buttons or logic switches as they keys that will play each note. The issue that i am having is that I don't think finding all of the perfect resistor and capacitor combinations for each note is a good idea. So, i...

Hello, I am new in computational chemistry. I was calculating by "Moller Plesset Second Order perturbation theory -MP2-" (using GAMESS) molecular parameters of Cs3Cl2-. Among them i found two complex frequencies of vibration. My question is now, what is the physical meaning of those complex...

Homework Statement Assume you have a symmetrical clock at 100MHz. Design a logic circuit with four outputs of clocks at 100MHz, 50MHz, 25MHz, and 12.5MHz. The logic circuit should have 2 inputs to select output clock rate. Homework Equations N/A The Attempt at a Solution For...

i'd like to know two things a) is there a theoretical upper and/or lower bound to electromagnetic frequencies in the universe? I'm thinking for an upper limit, 1/planck time? for a lower limit, i have no idea-- does Heisenberg uncertainty calculate into that? i suppose it would when you...

What does increasing the frequency of a computers main bus [the bus that connects the CPU to the chipset] imply about the voltage ["information"] traveling on a bus? (what IS the frequency of a bus effectively measuring, data units per second?) The way i see it (please correct me if I'm...

I just need a simple example, preferably one to do with voltage. thanks for any help :)

Homework Statement A thin beam of length L (flexural Stufness EI, cross-sectional area A, density p) is connected to a linear spring of stiffness K_s at each end. Derive the governing equation for the natural frequencies of transverse vibrations from the beam equation and boundary conditions...

Homework Statement A speaker is attached to a wire 1.5 m long and is spun in a circle at 2 rev/s. The speaker is connected to an electric piano on which a child is playing a note at 261 Hz. Speed of sound in air is 343 m/s. What range of frequencies will the stationary observer hear? I...

Maybe a dumb question, and I've been wondering this a long time, but the Haiti thing reminded me... Is it possible for electronically produced frequencies to cause seismic activity? I know that injection wells/fracturing/oil & gas wells/dams can cause induced seismicity, but is there anyway at...

Homework Statement A thin, flexible metal rod has a length of 0.606 meters. One end of the rod is clamped to a table, and the other end can vibrate freely. What are the first three natural frequencies of the rod if the wave speed in the rod is 27.4 meters per second? Hint: Draw pictures of...

Homework Statement The speed of transverse waves along a stretched spring is 9.05 meters per second. The spring is 4.70 meters long and is held in place at both ends. What are the first three natural frequencies of the spring? Hint: Draw pictures of what the spring will look like when it is...

Hello physicsforums members, I am an engineering student at Purdue University and am currently conducting research with regards to ribbon transducers. A ribbon transducer consists of a rectangular element of metal foil suspended within a magnetic gap (ie free at the sides) and...

Homework Statement If you blow air over the top of a fairly large drinking straw you can hear a fundamental frequency due to a standing wave being set up in the straw. Match the following actions with their consequent results: 1. While blowing, you cover the bottom of the straw with your...

Homework Statement A 0.0120 kg, 2.05 m long wire is fixed at both ends and vibrates in its simplest mode under a tension of 202 N. When a tuning fork is placed near the wire, a beat frequency of 5.10 Hz is heard. What are the possible frequencies of the tuning fork? (enter the smaller...

Just got a "thought experiment" question from a colleague. The question, as phrased was: If an audio signal was composed by adding all of the frequencies in the audible range, what would it sound like? I thought it was interesting, so I attempted to solve it by integral. My calculus skills...

Homework Statement Two tuning forks 384Hz and 256Hz. The question asks - would the sound of the combined frequencies be more similar to the 256 or 384Hz tuning fork. Estimate the frequency of the complex wave (noting that the pattern is repeated over three times). We are given two...

Homework Statement we are given a neutral pion moving at 0.98c straight in the x-direction. The pions rest mass is 135MeV/c^2. two photons are emitted in opposite direction parallel to the pion's motion. I need to find the two frequencies of each photon. Homework Equations m=0...

Homework Statement A certain dog whistle operates at 21.5 kHz, while another (brand X) operates at an unknown frequency. If neither whistle can be heard by humans when played separately, but a shrill whine of frequency 5000 Hz occurs when they are played simultaneously, estimate the...