String Definition and 1000 Threads

Homework Statement MUST USE RECURSION TO SOLVE THESE PARTS. Part A: Have a user input a string. Then display this string smashed up as follows: display the first character in the string, then the last, then the second, then the second to last, then the third... So if the string is “abcdef”, it...

Let's consider superstring theory on a 10 dimensional Minkowski background. And assume there is a D3-brane on which the open strings end and closed strings wander around freely in the background. I want to know, in what limit this gives a supergravity theory in which I can study it by using the...

Is supersymmetry part of string theory or does it have a place in the standard model

Homework Statement A pendulum traveling at constant speed along a circular path Determine the angle that the string makes with the vertical. T[/B]he length of the string was measured to be 60 cm. The period was measured to be 1.41 s The frequency was found to be 0.709 2. Homework Equations...

a light inextensible string passes over a fixed pulley A, under a movable pulley B of mass M and then over a second fixed pulley C. A mass m is attached to one end of the string and a mass 3m is attached to the other end. the system is released from rest. (i) prove that the tension t in the...

Hi Folks, Problem Statement How would one use the conservation of angular momentum to explain the attached picture? The rod is held fixed horizontally..the person holds on to the cork and then let's go...apparently the glass is saved due to this conservation... Relevant Equations Momentum...

A discussion with some friends: Suppose you have a large wheel, say 10 meters in diameter and a bell jar with a good vacuum inside, the wheel is rotating horizontally to Earth. In the jar is a bob, and it is on a 10 meter string which is connected to the center of the bell jar furthest from...

Homework Statement [/B]A traveling wave on a string is described by , 0.0050 sin[4.0 (rad/s) t + 0.50 (rad/m)x] . (a) Does this wave retain its shape as it travels? (b) In what direction does the wave travel? (c) What is the wave traveling speed? Homework Equations None. The Attempt at a...

Imagine that we wanted to build a slingshot, using one piece of rubber attached to two hooks - each on a side. We use a rubber, whose spring constant is k. My questions are: 1. If we began to string that slingshot and the rubber would begin to fold, what would happen with the string...

[Mod Note: moved to homework forum, template missing but homework-type problem] There are two masses (m) tied at two ends of a string of length 'l'. Whole system is placed on a friction-less surface and force 'F' is applied at the centre of string in direction perpendicular to the string. Find...

Homework Statement A uniform cylindrical drum of mass M and radius a is free to rotate about its axis, which i is horizontal. An elastic cable of negligible mass and length l is wrapped around the drum and carries on its free end a mass m. The cable has elastic potential energy \tfrac12...

Homework Statement A weightless string passes through a slit over a pulley. The slit offers frictional force '##f##' to the string. the string carries two weights having masses ##m_1## and ##m_2## where ##m_2 \gt m_1##, then find the acceleration of the weights. Homework Equations...

Homework Statement frequency, Tension, mass, mode of vibration Homework Equations v = sqrt(T/μ) The Attempt at a Solution length of string is 2.14m weight .00247kg mass per unit length (μ) .00089 However, I need to confirm this graphically. I solved for mass per unit length μ = T/V^2 or...

Urs Schreiber submitted a new PF Insights post Spectral Standard Model and String Compactifications Continue reading the Original PF Insights Post.

Move over, M- theory and F-theory! http://arxiv.org/abs/1609.06863 A brief review of E theory Peter West (Submitted on 22 Sep 2016) I begin with some memories of Abdus Salam who was my PhD supervisor. After reviewing the theory of non-linear realisations and Kac-Moody algebras, I explain...

Homework Statement This is actually a lab experiment which includes a stretched string which is clamped to one end with a G-clamp and the other end with a pulley and some masses hung from it. There's a bar magnet placed underneath the string near the pulley and a movable bridge to alter the...

In this note, the author says: with the following footnote: But I don't understand how that can be true. All the evidence for the cojecture arises from string theory: Similarity of Large N expansion and the perturbative expansion of a string theory and the equivalent low energy description of...

Roger Penrose’s http://press.princeton.edu/titles/10664.html']Fashion,[/PLAIN] Faith and Fantasy in the New Physics of the Universe "Arguing that string theory has veered away from physical reality by positing six extra hidden dimensions, Penrose cautions that the fashionable nature of a...

I was wondering why Quantum loop theory is still being followed FAIK it does not predict any thing yet, the same for string theory which seems to have lost its predictability, if these theories fail being tested where will we be It seems to me like super symmetry is the theory that every one...

I do not know why can they classify 5 theories of superstring.Is that correct that they base on different symmetries?

Consider an example of a mass hanging by a string. The string is fixed at the other end. The mass will be at rest because weight of the object is balanced by tension in the string upwards.Consider another example in which the other end of the string is not fixed. Now if that object is coming...

Homework Statement Let's have a disk and massless rope tangled in it. One end of rope is tied to the ceiling and the disk is falling freely down. System has one degree of freedom. As a coordinate we can choose angle ##\phi## which says an angle of rotation from the start position. Find from the...

A user types a word and a number on a single line. Read them into the provided variables. Then print: word_number. End with newline. Example output if user entered: Amy 5 Result should read as: Amy_5 import java.util.Scanner; public class SpaceReplace { public static void main (String []...

String Theory implies that the universe has 11 dimensions. If the 3 Dimensions represents space and the other one is time, what about the 7 dimensions??

Back when I was studying at Princeton University, J.A. Wheeler introduced me to Ed Witten while we were having lunch at the Institute for Advanced Study (IAS). I knew Feynman’s and Wheeler’s views on “String Theory,” and I had looked into it a bit as a field of research, but I couldn’t seem to...

What is the genesis of quantum foam, Planck constant, & string theory?

Loosely, in terms of string theory, an electron moving back and forth in a radiating antenna is a string moving in space-time. Far away, the electromagnetic radiation of the antenna is made of strings moving in space-time. Can I think of the near electric and magnetic fields surrounding the...

If so, how.

Homework Statement transverse wave is traveling through a wire in a positive direction of the x-axes. Distance od the wire particles in the motion of the wave can be described as ##y(x,t)=53*10^{-6}sin(188t-3.14x)## Find the ratio of the phase wave speed and maximal speed of the wire particles...

Homework Statement Two blocks are connected by a massless string that passes over a frictionless pulley. The coefficient of static friction between m1 and the table is 0.45. The coefficient of kinetic friction is 0.35. Mass m1 is 45kg and mass m2 is 12kg. Determine tension in the string. ***I...

Homework Statement You have a ukulele and you change the strings tension so that it becomes tighter. First the frequency was 431 Hz and after we tightened the string the frequency. how much bigger does the force have t be to get that frequency? Homework Equations PA*V^2 = F (P = density, A =...

If we study the high temperature limit (near Hagedorn) of a string gas, most of the energy is concentrated in a single long string. If we model the string by a fixed number of rigid links of length ls and calculate the number of possible configurations, we get the density of states: $$\omega(E)...

Homework Statement is 1222.5i 1 20.2j2 m/s . For that instant, (a) sketch a vector diagram showing the components of its acceler- ation, (b) determine the magnitude of its radial accel- eration, and (c) determine the speed and velocity of the ball. 42. A ball swings counterclockwise in a...

For the case of a particle attached to an inextensible string which is hanging at rest and then provided an impulse horizontally, what conditions must the system meet in order to allow for COMPLETE circular motion. I am well aware the tension at the apex of the motion must be satisfy one of the...

Hi all, concerned Dad here - looking for a validating opinion on the following and would be eternally grateful with some guidance/help. The attachment, Unit4ExamAQ7c is from one of my son's honor's exams. He gets #7c CORRECT with the answer v=2.29 m/s. However, the teacher grades him WRONG...

1. The problem statement, all variables and given/known Consider two objects with M1 greater M2 connected by a light string that passes over a pulley having a moment of inertia I about its axis of rotation. The string does not slip on the pulley or stretch. The pulley turns with friction. The...

Homework Statement Hi, sorry, I am not good at writing English, but I am trying. I hope that someone helps me solve the following problem. http://hodol.kr/q.jpg Please refer to the figure above. A stick(AB) of length 5 is leaning against the Wall(AO) and a string(CO) is tied at the...

Homework Statement A person would like to pull a car out of a ditch. This person ties one end of a chain to the car's bumper and wraps the other end around a tree so that the chain is taut. The person then pulls on the chain perpendicular to its length. If the distance between the car and tree...

Homework Statement This problem is a continuation of the problem I posted in this thread: https://www.physicsforums.com/threads/equation-of-motion-from-a-lagrangian.867784/ (We have set the mass per unit length in that question to ##\sigma## = 1 to simplify some of the formulae a little.)...

I am currently conducting an experiment where I attach a string to a fixed end and run the other end over a pulley (assuming zero friction). A weight is tied to the end to create tension. We currently have length, mass per unit -length and tension, the only issue is measuring the frequency of...

I have a physics homework question that i need help with; A submerged ball of negligible mass is attached to the bottom of a swimming pool by two strings as shown. The volume of the ball is 5000cm^3. Calculate the tension in each string. (hint you need to look up the density of water) How do i...

I was playing around with numbers and found that the equivalent temperature for Hawking radiation from a Planck mass black hole is ~5×1030 K. Later, I saw that the Hagedorn temperature for strings (where the partition function is expected to diverge) is reported to be around ~1030 K. I thought...

Homework Statement A 0.02 m x 0.01 x 0.03 block of copper (density = 8.8 g/cm3) is suspended submerged in milk (density = 1.03 g.cm3) by a string. How much tension is in the string? Homework EquationsThe Attempt at a Solution My initial thought for an equation was: T+Fb(buoyancy)-mg=0 T+...

Going through my physics assignment tonight, so that's 10 questions I'll be posting. Since I'm thoroughly hopeless at this subject most of my attempts will be based on my elite google-fu or trawling through lecture notes, bear with me and thanks! 1. Homework Statement frequency (f)=160hz...

Hi there. First of all, sorry for my bad english. I ´m trying to solve next exercise, from Vibrations and Waves in Continuos Mechanical Systems (Hagedorn, DasGupta): Determine the eigenfrequencies and mode-shapes of transverse vibration of a taut string with fixed ends and a discrete mass in the...

I there a simple hand waving explanation why strings "can oscillate in any spatial direction except parallel to momentum" (quote from below). I assume the yellow arrows below represent momentum. Edit, why not parallel to momentum? From an interesting read on the electron...

Homework Statement A horizontally oriented string with mass per unit length ##\mu=0.1kgm^{-1}## is under tension T=1.0N. The left end of the string moves up and down in a simple harmonic motion with an amplitude A=0.10m and frequency f=3.0Hz. This sets up a sinusoidal wave along the string with...

Homework Statement Hi everyone! Here is a new problem about oscillations! Thx to all of you, I'm definitely making progress in the field. Let's see how that problem goes: A pendulum of mass m is hanging on a string of length L and is "pushed" by a spring with spring constant k. At the deepest...

Hi all, I've been reading up on the physics of waves in order to better understand what goes on with sound. I'm having difficulties understanding how harmonics are produced in guitar strings. It's probably not as complex as I'm making it in my head, and it's really starting to frustrate me...

I need a light weight plastic material, like a string that is no more than 1/8 inch in diameter, that can be sewn into fabric alongside a zipper and spring open when the zipper opens. I would greatly appreciate any suggestions anyone is able to give. I have been trying to solve this design...