Frequency Definition and 1000 Threads

1. A sound wave of the form s = sm cos(kx - ωt + φ) travels at 345 m/s through air in a long horizontal tube. At one instant, air molecule A at x = 2.00 m is at its maximum positive displacement of 6.30 nm and air molecule B at x = 2.09 m is at a positive displacement of 2.40 nm. All the...

Has this been accurately measured yet? Google searches yield results for H 1s-2s and H 1s-3s transitions but not 1s-4s.

Hi all, I am trying to obtain an empirical equation/model having 2 inputs (frequency and S11) and one output (a physical parameter) I have done various simulations using CST of the System and now I am trying to relate S11 and frequency to a physical parameter. Any suggestions of how I should go...

This is not a homework question per se, but rather something I have come across during a homework project. Using Audacity, I recorded a few different instruments playing the same notes (investigating timbre). I noticed that (using a steel string acoustic guitar) the first harmonic at 131 Hz...

From textbook: "In much of the world (Europe, Australia, Asia) the rms voltage is 240 V, so the peak voltage is 340 V. The line voltage can vary, depending on the total load; the frequency of 60 Hz or 50 Hz, however, remains extremely steady" Why is it so important to keep it steady? what...

Homework Statement NOTE: Image uploaded with thread shows problem in clearest possible form. V = (45v)sin(80[pi] t) Resistors 1 and 2 = 50 Ohms Inductor 1 = 20 mH Inductor 2 = 2.5 mH Capacitor = 50 uF a) Find the power dissipated by each resistor. b) At what frequency will both resistors...

Homework Statement The current in a series circuit of R=5 ohms and L=30 mH lags the applied voltage by 80 degrees. Determine the source frequency and impedance. (Ans: Z=5+j28.4 , f=150.4 Hz) Homework EquationsThe Attempt at a Solution Current in the inductor, IL = Vm/wL*sin(wt-80) Current...

Homework Statement Please see attachment for diagram. The two boats are coherent sources of sound waves (phase difference ## \phi##) - i.e it's a double slit problem. Prove the formula given for ## y_{max}##. Suppose the whale is 20m long. How large should the sonar frequency ##f## be so that...

I've always just accepted that as you scale down a mechanical system the frequency and Q factor both increase. For example, this Wikipedia page simply says that "Small bells ring at higher frequencies than large bells". But for a driven damped harmonic oscillator, what is the exact relationship...

I am looking to find the resonant frequency of the amplified tuner circuit below The equation I have attempted to use is the f = 1/2*pi*√LC With the values for the inductance capacitance being 22pF and 47mH as I believe this is the tuner part of the circuit? The value I get by inserting these...

Can someone please explain intuitively how the terms “frequency” and “dynamics” are related ? I understand the concept of each of these two individually, but I am having some difficulty visualizing what high-frequency dynamics mean. I understand the concept of how time and frequency domains...

Homework Statement A spring is attached to the ceiling, a pulley is attached to the other end of the spring, a string is suspended over the pulley, and a mass attached to the free end of this string. The system oscillates vertically. Can someone PLEASE help me derive this equation for natural...

I've been a bit lost figuring out what damper I should be using for the front suspension I am designing. Right now I'm running a wheel rate of 60 lbf/in at the front with a ride frequency of 1.2254 Hz. The front is also supporting a sprung mass of 391.68 lbf. Comfort is the end requirement of...

Homework Statement A block of mass m is on a platform of mass M, supported by a vertical, massless spring with spring constant k. When the system is at rest, how much is the spring compressed? When the spring is pushed an extra distance x, what is the frequency of vertical oscillation...

The following question came up when me and a friend of mine were discussing some basic things about probability:Let $p$ be a real number in $[0,1]$. Does there exist a sequence $(x_1, x_2, x_3, \ldots)$ with each $x_i$ being either $0$ or $1$, such that $$ \lim_{n\to \infty} \frac{f(n)}{n} =p...

Homework Statement A radar receiver can be tuned to detect signals are different wavelengths. If the frequency difference between the minimum and maximum wavelength is 10 GHz and the minimum detected wavelength is 4910µm. What would be the maximum wavelength? Homework Equations λƒ=c The...

[Mentor's note: Thread title changed to reflect question content] I really need some help with this one: 1. Homework Statement An unhappy rodent of mass 0.307kg , moving on the end of a spring with force constant 2.48N/m , is acted on by a damping force Fx=−b⋅vx. Part A If the constant b has...

Homework Statement We have a spring of length l0 tied to two vertical non moving sticks. We place a mass m at 0,45l0 and let it oscillate. If we measure the period of an oscillation, we can find the angular frequency and calculate k. The question is, how can I calculate k1 and k2, the constants...

the following 2nd order differential equation is given: 2y'' + 4y' +8y=8x........(1) i want to find damping ratio, undamped natural frequency, damping ratio coefficient and time constant for the above system. solution: comparimg (1) with general system equaion (veriable can be exchanged)...

I'm under the impression that if you increase the frequency of a circuit coupled to an antenna, for the same amount of photons emitted, the frequency of those photons will increase therefore having them carry out more energy total, thus increasing the amount of energy required to power the...

Show that Planck's law expressed in terms of the frequency f is: u(f) = (8πf2/c3)(hf/(ehf/kT - 1)) from the equation: u(λ) = (8πhcλ-5)/(ehc/λkT - 1) When I do this algebraically by simply plugging in λ = c/f, I get: u(f) = (8πhc-4)/(f-5(ehf/kT - 1) which clearly doesn't involve the correct...

Ok, say I have a sine wave block that has a frequency of 60Hz. What can I do to get that frequency as a number so I can use it as an input to another block? I've tried various things such as a "sign" block that counts when it switches from positive to negative and then a counter that resets...

Homework Statement Two sound sources 15m apart producing identical 229 Hz sounds. As you move from one to the other, you hear beat frequency of 2.5. How fast are you moving?[/B] Homework Equations The question asks for the velocity of the observer Vo. The trick here is to use the standing wave...

This is a two part question and something I think I should know off the top of my head, but I don't, and I can't find a ready answer to it on at least a cursory search. The first part has to do with defining a frequency of a wave in general. I can sit here and tap out a beat on a drum that...

can we find the harmonic of vibration somehow just by knowing frequency?

I am trying to get used to using a Data Physics analyzer at work in order to measure the natural frequency of components of a larger project I am involved in, my method described is intentionally crude as I was trying to do this as a quick play around before diving into the real thing.. To...

I have an issue that appears to be relating to noise mitigation and grounding. Some background on myself is I have a mechanical engineering technology degree. But my job requires an ability to work with and troubleshoot electrical issues. Currently a customer is using a Servo motor on an end...

Imagine a massive object emitting photons of various frequencies. Because the object is massive, it will exert gravitational acceleration on those photons. Because the energy of a photon is proportional to its frequency, it seems that higher-frequency photons will experience a higher magnitude...

The start of the solution says to modify the Poisson to eliminate the case of 0 profit. I don't understand why this is the case or how to identify this type of problem as such. I don't see another way to reach the solution either... Thanks!

Can anyone give a solution or guidance about how to solve this. In vacuum, the components of an EM wave are Ey = 50(V/m)cos[(5.00 m-1)x + ωt], Ex = 0, and Ez = 0. What is ω?

I'm building an ultrasonic drill, and I've already collected or machined all of the components. Since I'm very inexperienced in electronics, I'm planning to simply buy an ultrasonic driver (power source) rather than build one myself. The one I'm interested in is here...

Hello, I'm currently studying for an exam and came across a question I can't seem to figure out. How exactly do we go about calculating the phase of a frequency response. Here is the question, it for part A) iii. Here are the answers to the other parts and the sketch of the magnitude: I know...

We all know that the electrical power = V * I * cos Q. and I know how this formula is derived. but yet intuitively I was expecting to see the frequency in the formula. I just need intuitive explanation how the frequency is not appearing in the power formula while we know in physics that higher...

my son is trying to find out how he can find an answer by being shown how to do the working out he wants to find out what the wavelength is if he only has the hz if he is 93.4 hz how does he find out what the wave lenth is thanks

Okay I have a question involving calculating the FFT of a signal from a sensor. I have simulated many different scenarios in MATLAB of various noise characteristics involving the signal. I want to take the FFT of a noisy signal. As long as my expected input signal has a higher amplitude than...

How to get specific frequency and time values for .wav file and export the values as .csv? Problem: I need to analyze this music .wav file, particularly for its frequency, amplitude, and pitch over specific intervals of time. Is there any easy to use software and steps I can take that can...

I'm struggling in physics class, and I really need help with this question. "If you are holding a spring in your hand and making waves, describe how to make a standing wave at the 2nd resonance frequency (next frequency over the fundamental). Include a sketch with your answer." What does this...

Note that I am not addressing only specular reflection here, but both kinds. Anyway, so if I had light of a certain frequency incident upon a surface, will the light that reflects off that surface also have the same frequency? That would imply that it had retained the full 100% of its energy...

Homework Statement I was given a task to model (using Matlab) 3 identical particles in external field and find spectra of lowest system energy states using gradient descend method for each particle in the system. I did a run of 500 random generated coordinates and found this distribution...

I know that in a vacuum, speed of light is constant. My question is more about the speed of light in a material like air. Dispersion of light in a prism tells us that the speed of light or the material index depends on the wavelength ( or frequency which is constant ) so I thought that air...

Homework Statement A truck moving at 36 m/s passes a police car moving at 45 m/s in the opposite direction. If the frequency of the siren relative to the police car is 500 Hz, what is the frequency heard by an observer in the truck after the police car passes the truck? (The speed of sound in...

Homework Statement The question and provided answer are given: Homework EquationsThe Attempt at a Solution I disagree with the answer. Shouldn't there only be three rising edge triggered d flip-flops? I say this because I know if I only had one d flip-flop with the inverter, the clock...

may i know how to calculate ringing frequency?

Hi, i am trying to find the natural period of a vertical cantilever beam which is fixed at bottom and free at other end., i worked out the global M & K matrices and i have the eqn in the form [M]-w^2[K] = 0, the M & K are not diagonal matrices, but square symetric matrices of rank 6. i...

Homework Statement Jane waits on a railroad platform while two trains approach from the same direction at equal speeds of 11 m/s. Both trains are blowing their whistles (which have the same frequency), and one train is some distance behind the other. After the first train passes Jane but...

Hello. Is anyone able to explain the 3 proportionality relationships present in Mersenne's Law, specifically in a conceptual sense? Mathematically they are easier to understand however it is difficult to understand them conceptually relating to strings. Any help would be appreciated. :)

This term is new for me so explain it simply ... and give a simple definition about cutt off frequency

Homework Statement In an NMR spectrum a CH2 group has a peak centred at 9.81 ppm. What is the shift in Larmor frequency of the protons from that of an unshielded proton if the spectrometer magnetic field is 9.4 T? The magnetogyric ratio of an unshielded proton is γH = 26.75 × 107 rad s-1T-1 2...

Homework Statement A trumpet player hears 3 beats per second when she plays a note and simultaneously sounds a 440 Hz tuning fork. After pulling her tuning valve out to slightly increase the length of her trumpet, she hears 5 beats per second against the tuning fork. What was her initial...

So I have some big speaker amplifiers at home, and they sometimes pick up radio interference from the CB enthusiast next door (he uses AM, so I'm guessing this is inducing a signal inside my amplifier which amplifies it into my speakers). It isn't really a big problem so I'm not looking for a...