Strings Definition and 523 Threads

Homework Statement Homework EquationsThe Attempt at a Solution the answer for d comes out to be 0.017 m. BUT, if we kept with tan instead of switching to sin, we would have mg(d/2)/ mg =kq q / d2 d^3 = 2k q q solving for d d = 0.0121 m clearly on a big scale, the two answers are about...

Homework Statement This is just a general question; but if there are two blocks attached with a string, how do you calculate acceleration and tension? Like, do you add the masses together and work with it, or do you do each separately? Also; if you have one block on an incline, and another...

How many strings of eight English letters are there that contain exactly one vowel, if letters can be repeated? My attempt: Let us first find the number of strings that contain at least one 'a' and no other vowels. Total number of strings including 'a' but excluding the other vowels $=22^8$...

How many strings of three decimal digits have exactly two digits that are 4s? Solution: 44x - 9 strings 4x4 - 9 strings x44 - 9 strings Total: 27 strings I get that. But what is wrong with this line of reasoning? I have two 4s with me. I have 3 positions for the first one and 2 for the...

Homework Statement A particle A is suspended as shown in the figure by two strings, which pass over smooth pulleys, and are attached to particles B and C. At A, the strings are at right angles to each other, and make equal angles with the horizontal. If the mass of B is 1 kg, what are the...

Homework Statement Homework EquationsThe Attempt at a Solution When string joining B is burnt , the forces acting on the rod are its weight , and tension in the left string ,both being vertical ,the acceleration of its COM would be vertical . Hence option A is correct . Now how should...

the news media has published the fact that there has thus far been no detection of gravitational waves as predicted by GR. eg Parkes Pulsar Timing Array found nothing after 11 years. If there are no gravitational waves, then GR is wrong. a common argument for gravitons is that there are...

Hello to all of you. I have the following case to solve. I have three overhead power line towers. The first and the third are with tension insulator strings, and the second is with suspension insulator string. During the design process i noticed that the second tower is located incorrectly and...

Homework Statement A weight is supported by 2 stings 1.3m and 2m long fastened to two points on a horizontal beam 2m apart. What is the depth of the weight below the beam? My question is- what does it mean by the "depth" of the beam? Homework Equations i'm new to the topic. The Attempt at a...

Homework Statement [/B] I have a string that's infinite on one side, as well as a string that's infinite on both sides. The displacement at the center (x=0) is the same for both, as shown in the pictures. Homework Equations [/B] I think the G term goes to 0 because there's no incoming wave...

Count the number of strings of length $8$ over $A = \{w, x, y, z\}$ that begins with either $w$ or $y$ and have at least one $x$ I don't understand this question at all. First of all, this is a set A that contains 4 elements $w,x,y,z$ correct? They are asking me to count the number of strings...

Homework Statement Two masses m and M (where M = 2m) are attached with strings. One mass m is suspended from a single verticle string held by two strings each at 45 degrees to the horizontal. The suspending string to the left at 45 degrees is attached to a fixed point. The string on the right...

When they say strings are one dimensional, do they mean that the height and width are really small that its only the length that matters? And if not, how can a one dimensional object exist if it has no height or width?

Are strings really just one dimensional? Is it possible that strings are 3 dimensional? Or even 10 dimensional?

I have just read this in a Brian Greene book, what does he mean by "they APEAR pointlike even when examined by the most powerful equipment" Seems very misleading, can soemone explain what led people to the theory of the strings existence. Surely they can't bee seen. here is the quote: "The...

This paper, http://arxiv.org/abs/1505.01584, Can Superconducting Cosmic Strings Piercing Seed Black Holes Generate Supermassive Black Holes in the Early Universe? offers a possible solution to the problem of SMBH abundances in the early universe at z~6. I suspended my abhorrence to the notion of...

what is string ; in fact

I'm revisiting python, because recently our physics department decided to adopt it as our computational language, and I missed the class. I've also been given the impression that it's a very good language for algorithms and what-not. According to...

Hi there! I have som troubles with representation theory. It is obvious that bosonic strings fields $X^{\mu}$ has zero conformal dimension $h=0$. But when one builds Verma module (open string for example) highest weight state has the following definition $$ L_0 \vert h \rangle = 1 \vert h...

Homework Statement A light string has its ends tied to two walls separated by a distance equal to five-ninths the length of the string as shown in the figure. A 67 kg mass is suspended from the center of the string, applying a tension in the string. What is the tension in the two strings of...

Homework Statement There's not a particular problem, per se, just that I seem to be missing something with my understanding of how to evaluate a string against a non-deterministic finite automaton with epsilon transitions. But one I've been working with is shown below Homework Equations NA...

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...

Homework Statement Homework Equations Accelerating force = F Resultant force = ma The Attempt at a Solution D is the correct option. Tension in string = T REsultant force = F - T = ma T = F - ma or if there is no friction, is the accelerating force the resultant itself? How do I proceed...

My question concerns motion of relativistic Strings, as the reader with a great a mount of deductive skills can deduce :). The question is: How can I derive the P's. More acuratly speaking why is the numerator how it is. I am referring to Zwiebach chapter 6. Thanks for any clarifications and...

Suppose there is a pulley (a disc) of mass m1 and a string passes over the pulley with masses m2 and m3 hanging on both ends of the string with m3 > m2. I know that the acceleration should be (m3 - m2)g/(1/2m1 + m2 + m3) and I know how to get there. However, since the pulley rotates and has...

Homework Statement Find the equation of the horizontal components of two strings tied to a painting at 45 degree angles with the horizontal.Homework Equations Fnet = 0The Attempt at a Solution Since the painting is in equilibrium, I found that, in the horizontal direction, Fnet = 0 = S1x -...

Homework Statement Calculate the horizontal force dFhorizontal of a string .Show that for small oscillations this force is much smaller than the vertical force dFvertical responsible for the transverse oscillations. [I apolagize for the way the equations are written] Homework Equations...

Homework Statement See image attached Homework EquationsThe Attempt at a Solution bii) Tc=mc(a+g) Need help on Ci what I did is (9x9.81) -uR-6g=10a Have no idea what to do though really

Hello, I have only recently begun learning about superstring theory and I have a few queries. one of which is this. Open string must have ther ends attached to a brane, I think I am right in saying that one end can be attached to one brane while the other to another separate brane. So in the...

I am currently reading Zwiebach and intend on reading Becker and Polchonski afterwoods. In chapter 4 he slves a partial differential equation with the Dirichlet and Neumann BC. My question is what the difference is between the two BC.(BC=Boundary conditions). Thanks for any help.

Homework Statement Two identical guitar strings are stretched with the same tension between supports that are not the same distance apart. The fundamental frequency of the higher-pitched string is 380Hz, and the speed of transverse waves in both wires is 200 m/s. How much longer is the...

Except for associating a statistical mean to a large number of measurements, how can one assign a single point to a particle ? Indeed, how can one assign a size of anything less than the Planck scale? A similar question about strings: how can one talk about one-dimensional objects? A similar...

Hi everyone. This is similar to my strcpy question previously. I tried to code but when I ran the code, a segmentation fault appears. I think this has something to do with my loop for the array but I have problems resolving it. May I have some help please? Thank you. My codes and the original...

Hi everyone. I ran into a problem while trying to code the string function, strcpy, without the use of <string.h>. The function, strcpy, which I have to make myself is exactly the same as the strcpy in <string.h>.The question in my homework is: Implement the my_strcpy(s1,s2) function that...

1. A hemispherical sign in 1m diameter and of mass equal to 50kg is supported by two strings. Calculate the tension in the strings. 2. W = mg 3. I tried to solve it but the only thing I was able to do is knowing the distance between the two strings which is 0.75m, I'm new to physics.

Homework Statement A weight is suspended by two strings at two different angles (the picture is included in the attempted solution) a.) Find the expressions for the tension in each of the strands b.) Assuming the tension, T1, does not change, what will be the acceleration of the weight if the...

This is a problem from my physics homework. I copied the diagram below as best I could from the text. It's not the best rendering but you'll get the idea. 1. Homework Statement Two blocks are at rest on a frictionless incline, as shown in the figure. Part A. What is the tension in the string...

Homework Statement three boxes connected by strings. given the mass of each box, coefficient of static and kinetic friction, and a constant speed of 2.0 m/s I want to know how to get force by a given speed...! Also, at a constant speed, how do I get to know the acceleration? does a = 0? if a =...

Something that's been unclear to me from the presentations I've seen of interacting string theory: In a setting like bosonic string theory, where the interactions consist of strings splitting and joining, is it always possible for a string to split? In other words, are there "minimum-sized"...

Hello everyone! I'm trying to make a transition diagram for an NFA that accepts strings that are either divisible by 5 or by 6. Here's the specific question: Question: Present a transition diagram for an NFA that recognizes the set of binary strings that starts with a 1 and, when interpreted as...

I'm trying to convert an integer variable to a string using to_string function of string.h header file. Here's the part of code: string numToStr=to_string(num); However, when I try to compile my program I get the following error: "error:to_string was not declared in this scope" I'm...

I am sorry if this sounds too philosophical but thanks for any inputs .. String theory claims that every particle in this universe is actually a manifestation of vibrations of fundamental strings. But how do these strings came into existence in the first place ? I understand the concept of...

Homework Statement While going over the exercises in my mechanics tutoring sheet I found that one of the problems' stated answer didn't make sense to me (it's apparently from a textbook): A weight of mass ##m## is fixed to the middle point of a string of length ##l## as shown in the figure...

I've heard that the strings in String theory are vacuums, is that right? And if so then how is it expected they form?

Just as particles move through the theoretical Higgs field and gain energy which gives them mass, do the strings in String theory get their energy to vibrate from the Higgs Field as well? And does that mean that the Strings have mass?

I need a little help with a project I'm working on. Here's the gist of it; I am taking two coils, hooking one into the input of an amplifier circuit and the other to the output. Both coils will be over an electric guitar string. The guitar string when vibrated will have a changing induction...

Which is the status of cosmic strings? Could they be related to inflation? Which are the most promising scenarios in which inflation arises/could arise in some way from a string cosmology? What do you think of the following papers? http://arxiv.org/abs/hep-th/0507205...

Homework Statement How many strings of five ASCII characters contain the character @ ("at" sign) at least once? [Note: there are 128 different ASCII characters.] Homework Equations The rule of product and inclusion-exclusion principle are relevant. The Attempt at a Solution The correct...

Hi all, I cannot understand how to do the following question from a practice test paper and urgently need help! For each integer n >=1, let tn be the number of strings of n letters that can be produced by concatenating (running together) copies of the strings 'a", "bc" and "cb". For example...

One of my interests in pi, and this is all purely recreational, is locating unique integers/relationships, looping numbers ( " orbits " ) etc. In pi, certain integers are located with a position number that when multiplied, by single integers, will return the number itself as a product...