String Definition and 1000 Threads

The problem statement: How many five-letter strings of capital letters have a letter repeated twice in a row? For example, include ABCCA and AAABC and ABBCC but not ABCAD. The attempt at a solution: First, let's break down how we would perform the selection of a string that meets the...

Hello, As I understand there is a problem in physics where point-like massive (or charged, etc.) particles would have infinite mass/energy (or charge, etc.) density. I'm curious how in the context of String Theory how we address the same problem? I have come to understand Strings as...

Homework Statement http://loncapa.vcu.edu/res/vcu/phys202/zzImages/Ch25_TB.jpg A charged ball with charge Q1 = 0.1 μC and mass 0.05 kg is suspended from a ceiling with a thin massless string as shown in the figure. The second charged ball has a net charge Q2 = -0.5 μC and it is located d = 0.3...

Homework Statement Two particle of mass m each are tied at the ends of a light string of length 2a. The whole system is kept on a frictionless horizontal surface with the string held tight so that each mass is at a distance ‘a’ from the center P (as shown in the figure). Now, the mid-point of...

Homework Statement "Find the tension in the right string, when the left string is cut, if the mass of the rod is ##m## and its length is ##l##, and ##\sin \theta = 3/5##. The rod is initially horizontal." Please refer the diagram below (sorry for its clumsiness!). Homework Equations $$I_{rod}...

Hi all! I am currently working on an assignment for my dynamics course in which we need to create our own "real world" problems. I chose to do a problem which would solve the time at which the string of a lanyard would break when it is swung in a circle. My problem is with my end numbers. They...

I am trying to compare a computer generated word to display the following however, when Quit is entered it produces the output "Hello". What is my error in the code? #include <stdio.h> #include <string.h> int main(void) { char userString[50]; strcpy(userString, "Quit"); /* Your...

Hello everyone, I would like to know if i can find in any of the Landau's books a chapter ,part concerning the flexible string ( differential equation , normal modes , stading waves ) ? I have tried to see but i can't find anything . There is a chapter concerning sound waves in a medium ( volume...

This is a question for the setup of a lab. I understand that the string must be tied to the mass and then spun in an overhead circle. A cylindrical tube with non-sharp edges will be used to spin the mass. Then, the string will be pulled through the mass, which would reduce the radius and...

string theory is a scalar-tensor theory of gravity, with higher order corrections. in light of the result discovery of gravitational waves of 2 black holes merging, matching GR in the strong field regime, how much deviation should strong theory differ from GR in the strong field regime and can...

Set hasDigit to true if the 3-character passCode contains a digit. #include <iostream> #include <string> #include <cctype> using namespace std; int main() { bool hasDigit = false; string passCode; int valid = 0; passCode = "abc"; if (hasDigit) { cout << "Has a digit." << endl; }...

What are some of the top graduate programs in Europe (excluding the UK) on theoretical physics specializing in string theory, fields or mathematical physics?

Homework Statement [/B] Consider a long chain of mass m and length L suspended from a tall ceiling. Like any string if one end is disturbed waves will travel along the string. However, the tension in the string is due to its own weight and is not uniform. As such the speed of the wave will be...

So I was reading our lecture notes about generalising the motion of a string by considering it as a system of N masses, and one of the arguments was that no matter where you are on the string, each mass element will oscillate with the same frequency. This makes intuitive sense for an ideal...

Homework Statement a 0.60 kg mass is attached to one end of a 1.7 m string. The string will break if its tension exceeds 60 N. The mass is whirled in a horizontal circle on a frictionless tabletop, such that the other end of the string remains fixed at the axis of rotation. What is the maximum...

Homework Statement ------------------------------------- |.\ |...\ |...\ |...\ Q...O P O=the bob Teta=60 degree The bob of a simple pendulum is released from rest at P. The mass of the bob is m and...

Homework Statement A violin string is vibrating at a frequency of 880Hz. How many vibrations does it make when the sound produced travels 332m through air at temperature of 0 degrees Celsius. Homework Equations Not sure. The Attempt at a Solution I'm not quite sure how to solve this equation.

Homework Statement the equation of a stationary wave produced on a string whose both ends are fixed is given by y= [0.6sin(pi/10)x]cos(600pi)t what could be the smallest length of string?Homework Equations k=2pi/wavelength The Attempt at a Solution i got the wavelength to be 20 but don't know...

Homework Statement A particle of mass m is on a massless string of length 3a, which is held horizontally across with a tension T(which you can assume doesn't change with the small vibrations). The particle is a distance of a from one of the edges. Set up a diff. equation that describes the...

Homework Statement Write a program (without using GMP library - https://gmplib.org) which performs arithmetic operations on large positive integers (addition, subtraction, multiplication and division). Maximum number of digits in one number is 100. Large number is the number that can't be...

which of the two is better supported by observational evidence and is more researched?

Is Brown a good university for string theory? I've checked out their website but was wondering about the general reputation and strength of the researchers in string theory at Brown. It does seem like a small school and guessing their acceptance rate would be low. Thanks

Homework Statement A light inextensible string of length l hangs on two pegs attached to parallel walls separated by a height. A small frictionless pulley of weight Wp is attached to a block of weight Wb. When it is placed on the string, the string becomes taut and pulley runs on the string...

Homework Statement Write a program that will square the input positive integer represented as a string. Homework Equations 3. The Attempt at a Solution [/B] Is there another way of squaring a string number instead of multiplying it by itself? Something like a pow() function for strings? If...

Homework Statement Homework EquationsThe Attempt at a Solution [/B]

The following article debates whether string theory is testable. https://www.quantamagazine.org/20151216-physicists-and-philosophers-debate-the-boundaries-of-science Even though they mention philosophy, this is not merely a philosophical debate. It a serious question for physicists as to how...

Homework Statement I'd like to better understand why the central charge is assumed to be equal to the number of dimensions in the spacetime background. Homework Equations By definition of Virasoro algebra and its operators: [Lm,Ln]=(m−n)Lm+n+c/12(m3−m)δm+n,0 The Attempt at a Solution The...

Why hello there my fellow science lovers, I'm some what new to the forums, and I'm loving it here. If this is being posted in the wrong section, I am very sorry. Anyways, I'm aware of the whole idea of the string theory. General relativity governs motion at a macroscale and quantum field theory...

Homework Statement I'm currently following the textbook Advanced Engineering Mathematics by Erwin Kreyszig. I'm learning the derivation of the Wave equation using the method shown in the book, but when I reached the final part of the derivation, the working just confuses me. (1/Δx)[ (u/dx)|...

Two doubts: First, when the hammer hits any string, the string begins to vibrate, until here, no problems, but, the vibration decays over time and this decay is linear, exponential or assume another form? Second, when the hammer hits a string and the string begins to vibrate, it vibrates in...

Various types of friction operate in all relative motion of materials. Boundary layers in the flow over on wings, Fatigue in metals subject the oscillatory bending. Friction between a car tire and the road. these are just some examples of the holistic impact on operations here on Earth. Does...

Homework Statement A 0.5 kg mass is attached to a string that is 20 cm tall and anchored to a pole. There is an angle between the string and the pole. 1) What is the force of gravity on the mass in terms of the angle? 2) If the mass is pulled slightly to an angle of 5 degrees and if sin(theta)...

In a lecture I heard that if we suspend two objects of different masses (and the system is accelerating) on both sides of a pulley of no resistance with a mass-less string then the tension on both sides of the string is same - this is fine till now. To explain that the tension is same, it was...

Homework Statement You have a long string, and you oscillate one end, causing a (transverse) wave to propagate along it. The wave's formula is D=0.40sin(7.0x+38t) where displacement D and position x are given in meters and time t is given in seconds. Determine the maximum and minimum...

Hallo. So the other day I reviewed a bit of quantum field theory and went through the Compton scattering calculation. To no ones surprise it was fairly simpel if you have a nice list of identities for rewriting the base results from the Feynman diagrams. See for exaxmple section 5.3 in...

Homework Statement A horizontal bar with a mass of 3.2 kg and a length L of 64 cm is rigidly mounted to a vertical spindle of negligible mass such that the two objects spin together. The spindle has a diameter of 2.0 cm, and it is attached to the bar a distance of L /4 from its centre of mass...

Homework Statement Since the image is not clear ,the blocks on the left are 1 Kg(top) and 5kg(bottom) connected by a spring. On the right are 1Kg(top) and 2Kg(bottom) .The bottom right string is cut . Homework EquationsThe Attempt at a SolutionSuppose T1 is the tension in string AB , T2 in...

Homework Statement A violin has an A string in tune at 440.0 Hz; as is the E string at 660.0 Hz. The tension force on each of the strings is 25.0 N. The linear density of the A string is 1.00 g/m. What are the frequency of the first three overtones for each string? Homework Equations f = v/ λ...

A string is wrapped around a uniform disk of mass M = 1.3 kg and radius R = 0.05 m. (Recall that the moment of inertia of a uniform disk is (1/2)MR2.) Attached to the disk are four low-mass rods of radius b = 0.08 m, each with a small mass m = 0.3 kg at the end. The device is initially at rest...

Homework Statement Here's the problem. I was able to find the a_n and b_n values, my question is mainly on part (c), how do I find which modes are missing? The function is odd, so even modes should disappear, but cos(n*pi) doesn't disappear, it's either +1 or -1. I'd greatly appreciate any...

I have heard that ST can calculate the masses of the particles species of some vacuum and also its decay rate, charge and so on, but I have not seen any clear paper on the subject. Can anyone point me to one? Are "hbar" and "c" the same in all the vacuums?why or why not? Can ST predict the...

Hello, before I start off, I apologize for asking a question which I am sure has been asked hundreds of times before: but I felt there is just way too much information out there which is a little confusing, so I am here with the hope of getting some personalized suggestions. I am currently a...

in string pulley systems(like atwood machine),the string applies a force on pulley of force 2T downwards,but why is it so? why should it apply that force? explain in detail

Homework Statement Hi all. What concerns me here is that it's worth 10 marks, but the solution I've tried only takes 2 steps. Am I missing some relation between the frame support and the pulley altering the components of the tension, or is the solution really just a basic trig conversion...

If you could magically go back in time, and spend two hours with Einstein shortly before he died in 1955, could you explain to him current modern superstring theory? If so, what would he think of it?

Can somebody please explain to me how the S-Matrix of Heisenberg and others helped influence the birth of String Theory. I keep hearing people say that String Theory came as a result of S-Matrix but I don't see the connection. Please keep maths to a minimal. Thanks.

I heard that in order for something to become a theory it must be tested.

hey can somebody suggest me some good books on string theory ...i am looking forward to join this field and i have no knowledge about this theory ... and some information about some colleges which are good for quantum physics and what's the future in this field of quantum physics... by the way i...

Hi all, Just curious as to whether it is a good rule of thumb ( though not an actual rule) that out of two effective queries (i.e., two queries q1, q2 that return the desired result) , the query that is shortest as a string, i.e., has the fewest total words, will run faster? I understand the...

I've gotten interested in this question since the recent loophole free bell test performed at Delft University (group of Ronald Hanson). In this test they use entanglement swapping which I hadn't heard about before. After some research I even found out that there is such a thing as delayed...