String Definition and 1000 Threads

Homework Statement A new musical instrument is fashioned from a metal can of length L and diameter L/10, open at one end, with a string stretched across the diameter of the open end. The string is tensioned such that the 3rd harmonic frequency of the vibrating string matches the fundamental...

Hi, I am new here! 1. There is no actually data given, I am just supposed to explain why a string that crosses a pulley have the same tension both sides. The pulleys moment of inertia is zero and friction is negligible. There is a little hint in this problem that says; study equation 9-15...

Hello everyone. I am an international student from China. Currently I received offers of a PhD position from both Caltech and Stanford. I applied for Hep-th and my main interests are formal field theories and string theory. I know both Caltech and Stanford are great schools in physics. And it...

according to book "...Let us look at a particular wave crest generated at the left end of the string by a fork. It travels to the right end of the string, is reflected back, and is reflected again at the fork.Now it interferes with the next wave..." doubt: the fork keeps vibrating and keeps...

Hi guys, To the experts of particle physics and of course to anyone else who knows and wants to share, what is the current status of string theory? Is there any progress? regress? are we stuck at a point (if so, I'd love to know which and why)? Thanks.

Homework Statement A string is sewn in a 2D membrane. What is the amplitude of the reflected wave? All the parameters you need in order to get to the result are known. Homework EquationsThe Attempt at a Solution Ok, so we have a 2D membrane, with a string at ##x=0## along the the ##y## axis...

Can resonance occur at multiple frequencies for the same given instrument? For example, in a violin, each note on a given string (say A) resonates and is the loudest only at a specific point on the string. Since each note on the same string can resonate, and each note has a different frequency...

Hello, I was recently reading a physics book and was told that, if a string were to hang down with a weight attached to it, its tension would be the mass times gravity. However, if it were to gain some velocity and move from left to right, the tension would increase enough so that the string...

Homework Statement I am stuck on this problem: So the question is asking for F21, F12, F32, and F23. (That's the force by 2 on 1). The mass of m2 is variable. There are four cases where I need to solve for the forces: when m2 has mass of 3kg, 0.3kg, 0.03kg, and 0kg. The mass of m1 = 2.5kg, the...

Homework Statement (Im translating this from another language, so if it doesn't make any sense, please let me know and ill try to do a better job.) A metal ball (mass=120g) is hanging from a string (lenght=85cm). The ball is struck horizontally. When the angle of the swing reaches 125 degrees...

Homework Statement http://puu.sh/frpk5/eae7bce2e3.png Homework Equations v = sqrt(T / (m / L)); The Attempt at a Solution 7.86 g / cm^3 = 7860 kg / m^3 T = v^2 * m/L T = 160 ^ 2 * 7860 which is a huge number I have no idea where the diametre plays a part.

Homework Statement Two masses M1 = 6.90 kg and M2 = 3.10 kg are on a frictionless surface, attached by a thin string. A force of 48.1 N pulls on M2 at an angle of 31.3° from the horizontal as shown in the figure. Calculate the tension T in the string. Homework Equations T=ma a=g(m2/(m1+m2))...

Homework Statement Suppose the rocket is coming in for a vertical landing at the surface of the earth. The captain adjusts the engine thrust so that rocket slows down at the rate of 2.40m/s2 . A 6.00-kg instrument is hanging by a vertical wire inside a space ship. I don't know if there are any...

Homework Statement The shape of the wave on the string at t=0 is: y=(2x)/(x^2+50) The waveform is moving in the +x direction at a propagating speed of 10cm/s. Find the displacement of the string in cm when t=5s and x=30cm Homework Equations ∂^(2)y/∂x^(2)=(1/v^2)*∂^(2)y/∂t^(2)[/B] The Attempt...

If a function f'(u) has Fourier coefficients anμ and bnμ, by integration one can make new coefficients Anμ ,Bnμ which include constants of integration. My question how can I verify that : Anμcos nτ + Bnμ sin nτ= -i/2 ((Bnμ) -Anμi) einτ- (Bnμ-iAnμ) e-inτ I assume this is the complex form of...

I want to make sure I have this right before I move on to the rest of this problem! 1. Homework Statement A string with mas M and length L is hanging freely and the mass is uniformly distributed along its length. Homework Equations a: Fend the tension in the string as a function of x, M, L...

Hi guys, So I'm a bit confused about why strings can't move at the speed of light. I understand that the end points do if the string is open, but the rest of it doesnt. To paraphrase, really I want to know why you must have timelike and spacelike tangent vectors to a point on the world sheet...

In string theory/M theory, there are two types of strings, open and closed strings. What kind of strings are fermions(electrons, quarks) made out of? Closed or open strings?

Homework Statement [/B] A string is wound around a uniform disk of radius ##10cm## and mass ##300g##. The disk is released from rest when the string is vertical and its top end is tied to a fixed bar. Determine the tension in the string. [ ##g = 10 ms^{-2} ##] Homework EquationsThe Attempt at a...

Homework Statement If you have a string being pulled on each end by 60N, what is the total tension in the string? Homework Equations N/A[/B] The Attempt at a Solution The answer in my textbook says 60N, but it doesn't make a whole lot of sense to me (even though it's obviously right). If...

Dears, What do you think, hypothetically, Einstein should think about String Theory?. Obviously, if he was here to study it.

Why is tension at a specific point in a string in 2 directions? For example in the first part of image 1, the string is pulling the two blocks upwards. And in the second part of image 1, the string is pulling the pulley down too. Does tension at a point in a string try to pull the point in 2...

Hey guys apparently the answer to this is 491 m/s, but i keep getting 34m/s by using a method whereby i find out the height reached by the block then using kinetic energy to potential energy... doesn't seem to work tho! Please help! A 50.0 g bullet is fired into a stationary 10.0 kg block...

Homework Statement A bit confused here as to what wave speed is dependent on. At first I learned that v = λƒ, and a couple of pages later in my textbook I find that v = √(τ/μ). Also, I found that speed is only dependent on the properties of the medium, specifically its elasticity and mass...

A bit confused here as to what wave speed is dependent on. At first I learned that v = λƒ, and a couple of pages later in my textbook I find that v = √(τ/μ). Also, I found that speed is only dependent on the properties of the medium, specifically its elasticity and mass. Where does wavelength...

I'm a beginning graduate student in string theory and I'm in the process of teaching myself algebraic geometry. I'm using lecture notes that go without mention of physics. I'm curious if there is a introductory book, or paper, or set of lecture notes that describes the application of alg...

Homework Statement A uniform chain of length L and [constant] mass per unit length λ is suspended at one A end by an inextensible light string. The other end of the chain B is held at rest at level of end A of the chain. [See image.] Now if the end B of the chain is released under gravity...

I'm currently in my final year at TCD and I'm looking at MSc programs in the UK in the areas of QFT, strings, CFT etc. The ones I know about are the obvious ones in London i.e KCL, Imperial, Part III, but they're out since London is so expensive and I'm extremely limited with funds. I've also...

Hello folks, I want to starting learning the subject this Christmas (Merry Christmas :D) and I am wondering what would be the best way to introduce me to Strings. I am a masters student in Theoretical Physics. Best wishes, and many thanks in advance. Breo.

My question is rather simple: How can I derive the equation for the change in action "delta S" ? If S is the Nambu gotto action.Thanks for any clarifications.

Hello Everyone, I want to know if it's a good time to study string theory from the basics? Or is it wiser to wait till next year, after the 2015 LHC run, if indeed we find any evidence for it? I have done a course in mathematical physics, classical and quantum field theory, electrodynamics and...

Homework Statement In a test, I was told to identify 3 characteristics that could increase the velocity of the sound traveling through a cup and wire phone. This was a sound and waves unit test. Homework Equations -- The Attempt at a Solution I wrote that the linear density could be...

Homework Statement Two blocks of equal mass m are tied to each other through a light string. One of the blocks is pulled along the line joining them with a constant force F. Find the tension in the string joining the blocks. Homework Equations I tried doing this by this method. (I don't know...

Assign the first instance of The in movieTitle to movieResult. Sample program: #include <iostream> #include <cstring> using namespace std; int main() { char movieTitle[100] = "The Lion King"; char* movieResult = 0; <STUDENT CODE> cout << "Movie title contains The? "; if...

I suspect my question will be somewhat unique, please forgive me if it's entirely out of place. (Please also forgive my ignorance when it shows, my knowledge of physics is extremely limited.) You might wonder why I'm asking it here, rather than on a guitar forum. Let me simply say that the...

Homework Statement A mass m whirls around on a string which passes through a ring. Neglect gravity. Initially, the mass is distance ##r_0## from the center and is revolving at angular velocity ##\omega_0##. The string is pulled with constant velocity ##V## starting at ##t=0## so that the radial...

if one string can hold a block of 100kg, how much weight can two strings connecting the ceiling and one single point hold a block?? is it 200 kg? if yes, then what about one string connecting the ceiling and one single point of the block two times, three times or more? [im sorry if the grammar...

Homework Statement A violin string with a mass of 0.35g is 33 cm long. The frequency of a wave supported by the string is 196 Hz. What is the speed of the wave? Homework Equations Ln = n/2 *lambda v = f*lambda The Attempt at a Solution 1. Solve for wave length [/B] L1 = 1/2 *lambda 0.33 =...

Hi. I am no physicist but I am trying to know something about the holographic principle. As I understand, everything is happening in a surface and our three-dimensionality is an illusion of our senses. On the other side, string theory assume the existence of 11 dimensions. Are the two theories...

Homework Statement A charged ball of mass 0.2[gr] and q=6E-9[Coulomb] hangs on a string between 2 plates that are 5[cm] apart. the ball makes 300 with the vertical. what is the voltage difference of the plates. Homework Equations Electric field: $$E[\frac{N}{Coulomb}]=\frac{V}{S[m]}$$ The...

Two strings are adjusted to vibrate at 260 Hz. One string is tightened then 3 beats per second is head when the string vibrate at the same time. What is the new frequency of the tightened string. I am using Fbeat=F1-F2; so wouldn't the answer just be 263 Hz

Hey! :o I have to write an $O(n^3)$ algorithm to determine whether a given string $w=a_1 a_2 \dots a_n$ is in $L(G)$, where $G=(N,\Sigma ,P, S)$ is a context-free grammar in Chomsky normal form. Could you give me some hints how to do that?? (Wondering)

Homework Statement A string of length L, which is clamped at both ends and has a tension T , is pulled aside a distance h at its center and released. a) What is the energy of the subsequent oscillations? b) How often will the shape shown in the figure reappear? (Assume that the tension remains...

Homework Statement A string is tied to a 4.4 kg block and 120g hanging bucket. Students add 20g washers one at a time to the bucket. The student are unaware that the[/B] coefficient of static friction for the block on the table is 0.42. A) what is the maximum force of static friction for the...

USE OF THE PHYSICS FORUMS TEMPLATE IS REQUIRED ON ALL HOMEWORK PROBLEMS. PLEASE COMPLY WITH THIS IN THE FUTURE. A string is tied to a 4.4 kg block and 120g hanging bucket. Students add 20g washers one at a time to the bucket. The student are unaware that the coefficient of static friction for...

Homework Statement https://www.dropbox.com/s/slpu1p8jplmxzmy/Screenshot%202014-11-18%2020.11.58.png?dl=0 Homework Equations Fnet = ma ma = (mv^2)/r The Attempt at a Solution ai) Ft up, mg down /\Ft I m I \/mg aii) both down m I I \/mg \/Ft aiii) Ft right, mg down m - >Ft I \/mg b)...

We have looked fairly extensively at waves on a string without anything on them, however there is a portion in my notes about an infinite string with a mass in the middle. Essentially the setup is that x=0 we have a mass. Here the waveform on each side must be equal as the string is continuous...

Complete the function to replace any period by an exclamation point. Ex: "Hello. I'm Miley. Nice to meet you." becomes: "Hello! I'm Miley! Nice to meet you!" Sample program: #include <iostream> #include <string> using namespace std; void MakeSentenceExcited(string& sentenceText) { <STUDENT...

Homework Statement Find the solution of the wave equation using d'Alembert solution. Homework Equations u(0,t)=0[/B] and u(x,0)=0 u_t(x,0)=\frac{x^2}{1+x^3}, \, x\geq0 u_t(x,0)=0, \, x<0 The Attempt at a Solution For a semi infinite string we have the solution u(x,t)=\frac{1}{2}\left(...

Homework Statement Assuming the keys are moving in uniform circular motion![/B] Keys with a combined mass of 0.100 kg are attached to a 0.25 m long string and swung in a circle in the vertical plane. a)What is the slowest speed that the keys can swing and still maintain a circular path...