String Definition and 1000 Threads

Homework Statement You swing a ball around a piece of string(vertically). M = 0.150kg r= 1.10m Calculate the Tention at the bottom of the arc assuming velocity is twice as fast. Homework Equations When I do the problem I'm not sure how to set up the NetForce = ma How do which force is...

I'm beginning to apply to grad schools (primarily in observational or computational cosmology and extragalactic astronomy) but have a deep interest in M-theory and quantum gravity although I haven't been able to study it. I very much enjoy theory and think that I would find studying M-theory or...

Could someone comment on, or perhaps help me fix/simplify/optimize/elegantify, a function I'm trying to make to split a string by whitespace into a vector of strings, discounting any whitespace in quotes? Intended behavior: name="someName" class="class1 class2 class3" id="someId"...

Homework Statement Find the maximum kinetic energy and total energy of the system if a string(with uniform linear density) of length L and mass M is oscillating as a standing wave with two fixed ends in its fundamental frequency f with amplitude 2A Homework Equations let x=0 and x=L be the...

Homework Statement A string is attached to a 10 kg block that lies on a horizontal surface. If the string is pulled horizontally with a force of 50 N, friction acting against it is 30 N. What is the tension in the string? Homework Equations F = ma The Attempt at a Solution Would it be 50 N...

I am trying to display the input that I enter into the dialog box from "inputdlg" function into a text file. This is what I've so far: prompt={['What is your name?']}; title = 'Name Machine'; answer = inputdlg(prompt, title); name = answer{1}; fileID = fopen('NameMachineFive.txt', 'w')...

When you pluck a guitar string it resonates at its fundamental frequency plus some of the overtones. My question is, what exactly determines the note (i.e. A,C, E etc) for, say, a guitar? For example, if note A is 440Hz then what is it that is at 440Hz because some instruments have lots of...

Greetings, I am intending on learning bosonic string theory in self study before new years eve and I nead a ruff and short introduction on the basics and the idea of gauge theory. The introducton is preferably in PDF form, yet books are fine to.

Homework Statement Mass m1 = 5.00kg is tied to the wall with a horizontal piece of string and is at rest onto of mass m2 = 10.00kg. A horizontal force F= 50.0N is applied to m2. The static coefficient of friction between all surfaces is μs = .350 and the kinetic coefficient of friction is μk =...

I'm trying to figure out what it says in my book. Here is the link of the picture. http://i941.photobucket.com/albums/...oads/7D0D3CE4-A11E-4F0F-A2A5-836D03945AE5.jpg Could someone explain the part where it says "Otherwise, there would be a net tension force acting on the sections, and they...

Consider the feynman diagramms for two freely propagating particles...Correction from one graviton exchange. Correction from two graviton exchange.The problem at hand is the divergence (of the math) at arbitary energys and each additional graviton exchange. So there are several resoultions and...

I am looking for introductiory books on gauge theory and conformalfield theory and polyakov integrals for research in Bosonic string theory. Any other material recommendations for String theory that are necessary for bosonic string theory or heterotic string theory are definelty apreciated. To...

Homework Statement Block 1, of mass m_1 =2.6kg and block 2 of mass m_2=1.4kg are connected by a massless string. Block 2 then experiences a force F=18N acting in the postivive x direction and at an angle of \theta = 38° . The coefficiant of kinetic friction between the floor and both of the...

I am losing my mind over this, it seems the longer i think about it the further i get from a definitive answer. It started with me trying to understand the variables the would result in a standing wave, ie: what needs to occur, why, and how it occurs. At first i was confused because it seemed...

Homework Statement [/B] A solid cylinder of mass m and radius r lies flat on frictionless horizontal table, with a massless string running halfway around it, as shown in Fig. 8.50. A mass also of mass m is attached to one end of the string, and you pull on the other end with a force T. The...

Homework Statement Two 0.400-kg carts are 100 mm apart on a low-friction track. You push one of the carts with a constant force of 2.0N directed so that the cart you push moves away from the other cart. Determine the acceleration of the center of mass of the two-cart system when the carts are...

In my wave course at the moment we are looking at waves on a string and their applications. At one point we consider the transverse force at a particular point on the string due to a uniform tension throughout a string. Something about this has confused me, the force isn't at all in the form I...

For the first part of the equation, I worked out k constant of a string which extended 12.6cm when a mass of 300g was suspended from it using the equation F = kx where F is the force applied and x its extension. So mg = xk, 300 x 9,81 = 0.126k, the answer was 23357N/m (23kN/m). The question...

The Polyakov action, S=\frac{1}{4\pi\alpha^\prime}\int d^2\sigma\sqrt{-h}h^{\alpha\beta}G_{ij}(X)\partial_\alpha X^i\partial_\beta X^j has the local symmetries, diffeomorphism on world sheet and the Weyl invariance. But is diffeomorphism on the target space also a symmetry? The target space...

Homework Statement Question: "The midpoint of a guitar string oscillates with an amplitude of 2.24mm with a frequency of 400Hz. Calculate: i) The maximum speed at this point ii) The maximum acceleration of the string at this point" Homework Equations Suitable formulas: x=Asin(2*pi*f*t) ...

Ok I understand the idea that a standing wave can be represented as the sum of two traveling waves going in opposite directions with same stuff but what I don't understand is why the waves on a guitar string are sinusoidal. I mean I know looking at them, they look sinusoidal but could they be...

This will, no doubt, sound like a silly question but I am just getting my feet wet in string theory. It seems from what I know so far, that string theory is very far removed from our observable universe. What I mean by that statement is that it seems we just say "well, maybe our universe is a...

Homework Statement A mass,m, hangs from a string and swings with a frequency of 0.8 Hz with a maximum displacement of 0.1 rad. The equation of motion is given by x=Acos(ωt). A) What is the length of the string? B) What is the maximum displacement of the mass in meters? C) What is the velocity...

Homework Statement A 65-cm guitar string is fixed at both ends. In the frequency range between 1.0 and 2.0 kHz, the string is found to resonate only at frequencies 1.2, 1.5, and 1.8kHz . What is the speed of traveling waves on this string? Homework Equations f = v/2l The Attempt at a...

Replace any space ' ' by '_' in 2-character string passCode. Sample program: #include #include #include using namespace std; int main() { string passCode; passCode = "1 "; <student code> cout << passCode << endl; return 0; } I'm super lost on this. I could...

Set hadDigit to true if the 3-character passCode contains a digit. Sample program: #include #include #include using namespace std; int main() { bool hasDigit = false; string passCode; int valid = 0; passCode = "abc"; <student code> if (hasDigit) { cout << "Has a...

Write an expression to detect that the first character of userInput matches firstLetter. Sample program: #include <iostream> #include <string> using namespace std; int main() { string userInput; char firstLetter = '-'; userInput = "banana"; firstLetter = 'b'; if (<STUDENT...

Assign the size of userInput to stringSize. Ex: if userInput = "Hello", output is: Size of userInput: 5Sample program: #include <iostream> #include <string> using namespace std; int main() { string userInput; int stringSize = 0; userInput = "Hello"; <STUDENT CODE> cout <<...

We have a string of length \(\ell\) with fixed end points. At \(x(a)\), we have a mass. We can break the string up into two sections \(a + b = \ell\); that is, a is the distance up to the mass and b afterwards. The string is under tension \(T\). My question is why is the DE then \[...

Homework Statement A block of mass M has a string of mass m attached to it. A force F is applied to the string and it pulls the block up a frictionless plane that is inclined at an angle theta. Find the force that the string exerts on the block Homework Equations F=ma The Attempt at a...

Assign the size of userInput to stringSize. Ex: if userInput = "Hello", output is: Size of userInput: 5 Sample program: #include <iostream> #include <string> using namespace std; int main() { string userInput; int stringSize = 0; userInput = "Hello"; <STUDENT CODE> cout <<...

Print the two strings in alphabetical order. Assume the strings are lowercase. End with newline. Sample output: capes rabbits Sample program: #include <iostream> #include <string> using namespace std; int main() { string firstString; string secondString; firstString = "rabbits"...

I've had a problem I encountered at work some time ago and took a personal interest in. I never did end up solving it, but I've recently looked at it again. It goes like this: You have an axisymmetric part, such as a cone, and it's positioned such that its central axis is coincident and...

Hi, so I'm new to this forum and wanted to ask for some advice. I REALLY am interest in string theory and I've read around the topic a lot without actually learning about it. In my school we can do an independent study project or ISP. When students do ISPs they have to have a project that can be...

Homework Statement In the diagram mA is equal to 3.00 kg and mB is equal to 1.07 kg. The angle of the inclined plane is 38.0° (a) Find Acceleration: 6.03 m/s^2 (got this part) (b) Find the tension Tb in the connecting string: Not sure Homework Equations (a) a = (F/mA + mB) (b) t =...

We have made a third film in our "Before the Big Bang" series for youtube. Our first centred around an interview with Abhay Ashtekar and focused on LQC Our second Sir Roger Pernose on CCC This fetaures an interview with Gabrielle Veneziano (founder of string theory), Ali Nayeri ( who works...

From what I have learned so far a wave propogates on a string by having the point on the string (that is closest to the wave and in the direction the wave is moving) move upwards or downwards depending on the wave and this point moving due to tension causes the next to move simillarly and thus...

Homework Statement A point mass M is concentrated at a point on a string of characteristic impedance ρc. A transverse wave of frequency ω moves in the positive x-direction and is partially reflected and transmitted at the mass. The boundary conditions are that the string displacements just to...

Hi, I'm trying to write a simple program for reversing a string stored in memory. This is what I've come up with. For some reason this code coredumps, so something is wrong. any ideas ? #include <stdio.h> #include <string.h> #include <stdlib.h> char *reverse(char *buf,unsigned...

Im a trying to understand how the string entity relates to its underlying field. Is the field a brane and the string the partice?

I am trying to capitalize the first letter of every word in a sentence. Example. "hey what's up" would be "Hey What's Up". here is my code but nothing is changing the sentence. I thought everything was right. public static String cap(String aString) { String[] sentence = aString.split("...

As Steven Weinberg put it, "the idea of quantum field theory is that quantum fields are the basic ingredients of the universe, and particles are just bundles of energy and momentum of the fields." At least, this is one way to look at QFT. The other approach is to imagine that these particles are...

Hello guys, I've had the following discussion at work: We are currently using a suture with a nylon thread on a tissue, when the thread of the suture is tightened in a force equal to if we've put a 500 gram weight on both ends of the suture line (meaning both end are tied together to the...

I feel curious about why we pay so much attention on standing waves on the string. Doesn't transverse wave on the string can't be used to produce sound?

Here's an idea that I came up with. I've heard over and over again that there is no test yet available to confirm string theory. So what I say is... What if you could derive some fundamental physics equation from string theory principles? Then wouldn't that be a test so to speak...

A disk of mass M and radius R is held up by a massless string. (The two ends of the string are connected to a ceiling and the disk rests on the bottom of the string.) The coefficient of friction between the disk is μ. What is the smallest possible tension in the string at its lowest point...

I was teaching myself standing wave's chapter. It is said in the book that when plucking in the center of the string, it will cause two traveling waves of different directions, one left, one right. Then both of them will reach ends of string and invert back. Before they encounter at the center...

Hi all, I cannot seem to find a way to justify my book's answer to this problem: One end of a string is shaken each second sending a wave with an amplitude of 10cm toward the other end. The string is 5m long and wavelength of each wave is 50cm. How many waves reach the other end of the string...

String effective action: S=-\frac{1}{2\lambda_{\text{s}}^{d-1}}\int d^{d+1}x\sqrt{|g|}e^{-\phi}\left[R+(\nabla\phi)^2+2\lambda_{\text{s}}^{d-1}V(\phi)-\frac{1}{12}H^2\right]+S_m where H^2=H_{\mu\nu\alpha}H^{\mu\nu\alpha}\\ H_{\mu\nu\alpha}=\partial_\mu B_{\nu\alpha}+\partial_\nu...

This is a question currently pondered by many Quantum physicists and theoretical physicists. I was just wondering how many of you prefer ST(string theory) as opposed to LQG(loop quantum gravity.) Please provide points and reasons regarding your answer. I will provide an opinion when a few...