String Definition and 1000 Threads
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Standing waves on a string -- Find the difference of phases
The immediate thing i did here is ## \Delta \varphi = k(\Delta x) ## Interesting enough for a topic, if you use this equation you end up wrong like me, the answer is not D. Not sure what is the problem.- LCSphysicist
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- Difference Phases Standing waves String Waves
- Replies: 5
- Forum: Introductory Physics Homework Help
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Comp Sci How to Structure Java String Code in a Static Main Method?
here the class name is test153 sent is the sentence entered l is the length of the sentence w is the variable storing each word temporarily before printing.- anyonebutangel
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- Code Java String
- Replies: 2
- Forum: Engineering and Comp Sci Homework Help
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A Sum over backgrounds in String Theory
Usually, I saw that string theory (perturbative, or matrix models) are made in a fixed background. Even if you consider that the metric is quantized and etc. there is an apparent physically motivated need for making a sum over topologies (manifolds, conifolds, orbifolds, and etc), for example...- Iliody
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- String String theory Sum Superstring theory Theory
- Replies: 4
- Forum: Beyond the Standard Models
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Please help with a problem displaying a string using pointers
Hi I wrote a program to copy an array of C-String into dynamic memory in the function using pointers. I think I did it right, but I cannot display without garbage at the end of the string. //10.9 function copy C-String using pointer #include <iostream> using namespace std; void strCopy(char**...- yungman
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- Pointers String
- Replies: 5
- Forum: Programming and Computer Science
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A traveling wave on an infinite string, find the intensity
The answer is about 40 Watts, but i am really not getting it: <Pot> = 0.5((pλ)(ωA)²)v p density linar λ wavelength ω angular frequency A amplitude v phase speed Why is this wrong? (I already tried too by <Pot> = Z*(ωA)²/2) Z is impedance- LCSphysicist
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- Infinite Intensity String Wave
- Replies: 5
- Forum: Introductory Physics Homework Help
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Does the tension in a string act on the body to which the pulley is attached?
The normal reaction from the ground and from block m, the force of gravity are the forces I feel should act on the wedge but since the wedge is a perfectly rigid body and the pulley(which is massless) is attached to it so will tension also act on the wedge as well?- Hamiltonian
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- Act Body Pulley String Tension
- Replies: 13
- Forum: Introductory Physics Homework Help
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Did I Make a Mistake in Analyzing the Oscillating String?
I thought we could do the part a by two steps: (Studying the motion along x {there is no}) and along y (Here should be T + dT)****** But apparently the answer is: "" So i think if the answer is wrong or, if not, where i made a mistake?- LCSphysicist
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- Oscillating String
- Replies: 2
- Forum: Advanced Physics Homework Help
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Trajectory of a mass element in a string overhanging a pulley
Hello everyone, this is a thought experiment I made, it involves two ropes being pulled of a pulley similar to an atwood machine, and a block attached to the two pulleys at the other end. The ropes are being pulled at a constant velocity $ U$ from the end away from the block and the block rises...- burian
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- Element Mass Mechanics Pulley String Trajectory
- Replies: 19
- Forum: Introductory Physics Homework Help
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How do I read this equation for air friction/drag on an object?
I am trying to understand an excerpt from an article describing the vibrations of a string (eg. guitar/piano) which reads as follows: This is basically the wave equation with Δm representing a small piece of mass from an interval of the string and two forces added to the right side. He... -
Total energy of the normal mode on a string
What you think about this question? Seems a little strange to me, that is, it considers the maximum kinetic energy when the displacement of the oscillators is maximum, i don't think this is right.- LCSphysicist
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- Energy Mode Normal Normal mode String Total energy
- Replies: 3
- Forum: Introductory Physics Homework Help
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B Size of strings in string theory
Quite a long time ago, I read about length of strings in string theory. And, if I remember correctly, expected length was in light years. I looked at Wikipedia today, and I see currently expected length of string is very small, around Plank size. Is it changed over time, or the expected length...- Ans
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- String String theory Strings Theory
- Replies: 11
- Forum: Beyond the Standard Models
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Fundamental frequencies in a violin string.
Why is this wrong?: That is, why is not f = 4fo? Oh. And my figure 1 can be wrong, because maybe i got confused if the string was open or closed in the boundaries, anyway this change nothing the relations (1)- LCSphysicist
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- Frequencies Fundamental String Violin
- Replies: 3
- Forum: Introductory Physics Homework Help
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Question about Waves on a String
Summary:: Could you send a second wave pulse down a string that would overtake an earlier wave pulse? Got this question in my physics textbook. Ignoring reflection (i.e., you had a very long string), say you send a transverse wave pulse down a string fixed on its other end to a wall. Could you...- Abdullah Almosalami
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- String Waves
- Replies: 2
- Forum: Introductory Physics Homework Help
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A Can Cosmic Strings Trigger Vacuum Decay?
https://arxiv.org/abs/2002.04856 It's proposed that topological defects like cosmic string enhance vacuum decay. I do not quite believe it. -
David Morin classical mechanics Problem 2.6: Disk held up by a massless string
The first part is easy, we have 2T= Mg T= 0.5 Mg Now for the second part where I'm having trouble understanding Morin's solution: I take the normal force on a small circle arc to be N, we know that the y component of the normal force must be balance with Mg for the whole disk, therefore Ny =...- John100861
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- Classical Classical mechanics Disk Massless Mechanics Morin Statics String Tension
- Replies: 5
- Forum: Introductory Physics Homework Help
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Lagrange equations: Two blocks and a string
I've problems understanding why the kinetic energy of the string is only $$T_{string}=\frac{1}{2}m\dot{y} $$ Why the contribution of the string in the horizontal line isn't considered?- Zamarripa
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- Blocks Lagrange Lagrange equation String Two blocks
- Replies: 9
- Forum: Advanced Physics Homework Help
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A string over a pulley with two hoops wound like spools on each end
I have seen the solution to this problem but I don't understand it. Here is my drawing of the problem. Apparently I should do the sum of the forces and sum of the torques for both hoops like this: hoop 1: (1) τ - M1g = M1(a1t-a1R) (2) τR1 = ½M1R12a1r/R1 hoop 2: (3) M2g - τ = M2(a1t+a2r) (4)...- pleasantresult
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- Pulley String Wound
- Replies: 9
- Forum: Introductory Physics Homework Help
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B String Theory & Elementary Particles: What's Real?
If string theory is correct does it mean that elementary particles like photons, electrons, and quarks don't really exist or does it mean they do but are made of cosmic strings and so therefore are not elementary?- Jupiter60
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- Elementary Elementary particles Particles String String theory Theory
- Replies: 12
- Forum: Beyond the Standard Models
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Comp Sci Troubleshooting String and sscanf in C: How to Get Correct Output | Example Code
#include<stdio.h> int main(){ char str[]="My first book"; char *a,*b,*c; sscanf("%s %s %s",a,b,c); printf("a=%s b=%s c=%s",a,b,c); } I want the output: a= My b=first and c=book. But it does not work, why?- anonim
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- C code String
- Replies: 7
- Forum: Engineering and Comp Sci Homework Help
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A Is Stochastic String Theory the Key to Original Ideas in Physics?
Well there was today some lecture on String theory which I got late since I was reading something else in Condensed matter physics and then I looked at a book that I have of stochastic Integration with jumps and by associativity of ideas I searched google for Stochastic String Theory and got to...- MathematicalPhysicist
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- Stochastic String String theory Theory
- Replies: 2
- Forum: Beyond the Standard Models
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Calculating Period of System with Masses, R & dX
Here is the picture on the system. I have to find the period (T). The masses, R and dX is given. The systam at first is at rest, then at t = 0 we pull the plank to dX distance from its originial position. In the thread...- Hohen
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- Cylinders Dx Harmonic motion Lagrangian mechanics Mechanics Period String System
- Replies: 17
- Forum: Introductory Physics Homework Help
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Waves and vibrations on a string
Q.1. The length of a stretched string fixed at both ends has a length of l=10 cm, mass per unit length ρ= 0.01 gm/cm. If the tension ' T ' is produced by hanging a 11 kg weight at both ends of the string, then calculate, a) The wavelength of the first two harmonics, b) The speed of the wave...- Diku Khanikar
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- Oscillations String Strings Tension Vibrations Waves
- Replies: 2
- Forum: Introductory Physics Homework Help
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Find the tension in the string of this two mass system
I know that it will probably execute something similar to circular motion. I thought of conserving momentum but I think there is an external force being applied due to the impulse which will prevent me from doing so. I know that once I find the tension it would become very easy to find the...- PSN03
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- Mass String System Tension
- Replies: 27
- Forum: Introductory Physics Homework Help
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What units for the wave function of a string?
hello , hope all of you are doing well , i have question about the unit of the function of waves of string fixed in both boundary , the function of waves is function of two variables x and t , so it's function describe the displacement in function of place and time , Ψ(x,t)=φ(x)*sin(ωt+α)...- Zouatine
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- Function String Units Wave Wave function
- Replies: 1
- Forum: Introductory Physics Homework Help
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Two blocks connected with a small string pulled up a ramp by string
- TjGrinnell
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- Blocks Ramp String Two blocks
- Replies: 3
- Forum: Introductory Physics Homework Help
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Waves Homework help -- Waves on a String
Okay well I'm stuck on this one. I know that lamba times frequency is wave speed and 1/f is period. I think that the wavelength of the wave is four but what is the frequency? (1/2)? Would I multiply 4*1/2 to get 2 m/s as the wave speed and then if the frequency doubles to .25, the wavelength be...- Riemannenthusiast
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- Homework String Waves
- Replies: 10
- Forum: Introductory Physics Homework Help
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Wave Equation: d'Alembert solution -- semi-infinite string with a fixed end
Hi, I was trying to get some practice with the wave equation and am struggling to solve the problem below. I am unsure of how to proceed in this situation. My attempt: So we are told that the string is held at rest, so we only need to think about the displacement conditions for the wave...- Master1022
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- D'alembert String Wave Wave equation
- Replies: 4
- Forum: Calculus and Beyond Homework Help
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Standing Waves Homework: A Tuning Fork, a String and a Hanging Mass
Hi guys, so I am struggling on the Standing Waves concept. I understand that these are waves that move in place but I don't know how to attempt this problem. Can someone set me on the right track?- chessmaster62
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- Homework Mass Standing waves String Tuning Tuning fork Waves
- Replies: 1
- Forum: Introductory Physics Homework Help
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Calculate the density of the material for a vibrating string
Here is the question that is is given to me Part a: Part b: I have given this a go and was wondering if my answer seems reasonable. I had worked out that the mass per unit length (mu) is also the density * cross sectional area of wire Thanks!- Bolter
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- Density Material String
- Replies: 1
- Forum: Introductory Physics Homework Help
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What is the frequency of the second harmonic on the A-string in guitar tuning?
We’re tuning a guitar using harmonics, and we produce, on our properly tuned E-string, a frequency of 329.6 Hz when we pluck the first harmonic. The second harmonic, on the A-string, is noticeably higher, producing a beat frequency of 1.5 Hz. What is the frequency produced by the harmonic on the...- RicoY65
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- Frequencies Guitar String
- Replies: 3
- Forum: Introductory Physics Homework Help
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Representing Logical Combinations in Analysis Programs
I have an analysis program. (It's MCNP if it makes any difference.) Part of the input is to specify the surfaces of a cell in a string of "this side of surface x" and "that side of surface y" entries. It looks a little something like this. ((a b):(c -d)):(f -g)) So the : means "or" and...- DEvens
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- String
- Replies: 10
- Forum: Programming and Computer Science
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Comp Sci Return the number of times a word appears in a string
def count_code(str): count = 0 for c in range(len(str)-1): if str[c] == 'c' and str[c+1] == 'o' and str[c+2] == 'd' and str[c+3] == 'e': count+=1 return count Here is my code so far, I did use some test results with print...- ver_mathstats
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- String
- Replies: 11
- Forum: Engineering and Comp Sci Homework Help
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A Can Cosmic Inflation and String Theory change fundamental laws?
Is there any version of string theory or cosmological inflation that allows the most fundamental laws and constants change between universes? String Theory and Cosmological Inflation are two theories or models that allow multiple universes to exist. Laws and constants of physics could change...- Suekdccia
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- Change Cosmic inflation Fundamental Inflation Laws Laws of nature Multiverse String String theory Theory
- Replies: 4
- Forum: Beyond the Standard Models
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To find the amplitude of a mass on an elastic string
Could I please ask for help with the following: It's the final part I am having problems with. So at this point we know we have SHM of amplitude (5/4)L Now, using x = a cos(nt) ----- where we now know that n = sqrt(4g/L) we can find the time at which x has any value. So for exmaple, when...- gnits
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- Amplitude Elastic Mass String
- Replies: 7
- Forum: Introductory Physics Homework Help
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Timoshenko Beam Theory (Violin String Shape Functions)
Homework Statement:: Violin String Shape Functions Homework Equations:: Violin String Shape Functions Hello, Is anyone working on violin string shape functions(Timoshenko Beam Theory)? It would be really helpful to my research if we share our knowledge on this topic. Thank you- Srinath
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- Beam Beam theory Functions Shape String Theory timoshenko
- Replies: 1
- Forum: Mechanical Engineering
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How Do You Calculate the Tension of a Cello String?
wavelength of string= 2*L wavelength of string=2*0.70m= 1.4m velocity of string= frequency * wavelength velocity of string= 220Hz * 1.4m= 308 m/s tension= (308m/s)^2 * 0.00196 kg/m =186N Is the tension correct?- ac7597
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- String Tension Wave Wavelength
- Replies: 1
- Forum: Introductory Physics Homework Help
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To find the equilibrium position of a mass attached to an elastic string
Hi, can anyone see if I have made an error in answering this simple question, my answer is not the one given in the textbook. Here's my diagram of the system in equilibrium. So the mass has dropped a distance x below the midpoint of PQ: So the forces balance as: T1 = g + T2 So, using...- gnits
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- Elastic Equilibrium Mass Position String
- Replies: 17
- Forum: Introductory Physics Homework Help
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Length of a string over a 2 pulley system
Hello all, I am working on a lab report for physics, and am a bit stuck on one aspect. The basic layout of the pulley system is attached. (This is a diagram I made, so if there are any inaccuracies in this one either, I am happy to fix it. So, I mostly understand the lab. My TA said, though...- breid040
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- Length Pulley Pulley system String System
- Replies: 7
- Forum: Introductory Physics Homework Help
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Travel time of a particle suspended from an elastic string
Hi, Can anyone please help me with the following: I have found the velocity of projection, no problem, it is v = 2*sqrt(10) Also, in obtaining this value, I have also found the extension in the string when in equilibrium, it is x = 2 Now on to the time of flight. The given answer is: t =...- gnits
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- Elastic Particle String Time Travel
- Replies: 6
- Forum: Introductory Physics Homework Help
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How Does String Tension Affect Audio Output Amplitude in Synthesizers?
I am working on a guitar/piano synthesizer for my own interest. When a string is plucked or struck, tension increases causing a slight pitch bend and change in the inharmonicity. This change then settles as the note quiets down. Thus it is important to model how the tension rises above baseline... -
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Whats the tension T' in string 1 if tension of highlighted string is T
- Physics freak
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- Newton mechanics Pulley system String Tension
- Replies: 1
- Forum: Introductory Physics Homework Help
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Find the Total Energy of the String
Steps that I've taken: First, compute the derivative of the psi-function with respect to time and then take the square of the result Second, input the result into the KE integration formula. All that is left is to find the integrand, however this is where calculations became really "messy". It...- Aerimiel
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- Energy String Total energy Vibrations Waves
- Replies: 1
- Forum: Advanced Physics Homework Help
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Addition of Harmonics in a string wave
In basic optics, we are given the general solution of the wave equation (massless string of length L) as a linear combination of normal modes, that need to have some of the permitted frequencies due to boundary conditions. In laboratory, we observed that phenomenon. We generated a wave in a... -
Are harmonics "real" in a vibrating string?
This question reminds me of the interpretation of the "wave packet" in QM for a free particle moving freely in the whole space; but in QM it is obvious that plane waves can't be of physical meaning. Now consider a guitar string (fixed at both ends) and suppose the solution to the wave equation... -
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MHB TM: Is the given string of the form uu?
Hey! :o I am looking at the following exercise: Construct a composite Turing machine $M$ that has a word $w$ over the alphabet $A = \{a, b\}$ tests to see if it's made up of two equal parts, that is, if $w = uu$ with $u \in {a, b}^+$. In this case, at the end of the method a $1$ has to be...- mathmari
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- Form String
- Replies: 4
- Forum: Programming and Computer Science
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Tension in the string while it descends
so I took string below point A and Block as a system. Taking mass of string below point A as m and mass of block M. Taking downward direction as X axis. I get Mg+mg-T, Taking T as tension by upward part of string. Now the question says about block descending with acceleration a. so again forces...- Asterast
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- Newtons second law String Tension Tension in string
- Replies: 8
- Forum: Introductory Physics Homework Help
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Tension in a String: Solve for Unknown Lengths - 98.6N
I know that the answer has to be 98.6N. So I know that Fy=0 so that 2*T*sin(theta) = 147.25. Then I was think to take the torque of the left wheel but I can't find the lever arm of the tension force. I also know that u can solve the question by saying that the 2 sides of unknown length are 1.5 m...- snormanlol
- Thread
- String Tension
- Replies: 5
- Forum: Introductory Physics Homework Help
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A string attached to a fixed wall and a mass on a spring
Hi all. Multiple part problem that I'm really stuck on. I'll attach a file. At first I had attempted the whole problem with the idea that fixed wall was a fixed point, and that the mass on a spring was a "free" point. But I learned later that the mass can't be treated like a "free" point since...- Old-Alien
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- Mass Spring String Wall
- Replies: 10
- Forum: Introductory Physics Homework Help
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A Real image of a sawtooth standing wave in a musical string?
Hi there I am teaching resonance and standing waves in stringed instruments at the moment at high school. The theory states that a number of standing waves simultaneously (harmonics) exist in a naturally vibrating musical string, but with varying amplitudes, the 1 st harmonic being loudest...- pkc111
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- Image Real image Standing wave String Wave
- Replies: 41
- Forum: Other Physics Topics
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B How Does a Man Accelerate While Climbing a Rope?
A man tries to climb up a rope with acceleration, ## a ##. What does he actually do to climb up? My Interpretation Let the man pull the rope at point A. So the Point A will pull the man with Tension, ## T ##. But at the same time the man is holding the rope, so there will be some normal...- Kaushik
- Thread
- Friction Rope String Tension
- Replies: 34
- Forum: Classical Physics