String Definition and 1000 Threads

Circular momentum - Tension of a string. Homework Statement A body of mass 1kg is tied to a string and rotates on a horizontal frictionless table. If the length of the string is 40.0 cm and the speed of revolution is 2m/s, find the tension in the string. 2. The attempt at a solution...

Hi suppose i had a ball on string and started to rotate it in a circle around my hand. When i increase the speed of the ball it becomes more and more horizontal. The only forces i can think of at play is centripetal and centrifugal forces and the force exerted by my hand and gravity. Is somehow...

Hello everyone, I'm working with a design team to take quick and accurate measurements of the middle upper arm circumference in third world countries to assess malnutrition in children. One of the issues in taking measurements is people pulling variably on the tape measure around the arm. My...

Consider me physics illiterate since my last class was advanced placement physics in high school (over 20 years ago). I am trying to understand what the title says, How does quantum entanglement, string theory, and the BB fit together? Skipping to the meat of the subject, everything revolves...

Homework Statement This is a lab question. Basically what the lab entails is we have two spheres. One is suspended from a string and another is attached to a non-conducting rod. We inductively charge the sphere attached to the rod. Then we bring it close to the other sphere that is being...

when we tie a stone to a string and spin it,it does not seem to fall.why does it happen?i mean to say that,no matter how great its horizontal velocity and centripetal force is,the vertical component of the acceleration won't be affected.it means that the stone should keep falling no matter how...

Homework Statement In the Atwood's machine below the string passes over a fixed cylinder of mass mc. The cylinder does not rotate. Instead, the string slides on its frictionless surface. (Use any variable or symbol stated above along with the following as necessary: m1, m2, and g. Find the...

A meterstick (L = 1 m) has a mass of m = 0.13 kg. Initially it hangs from two short strings: one at the 25 cm mark and one at the 75 cm mark. What is the tension in the left string right after the right string is cut? Calculating the free body diagram where we put the acceleration...

I was watching a video on string theory and they claim that its all vibrating strands of energy. I thought energy was just a property of the system, not a physical entity. So do they mean something else by "energy"?

Homework Statement I am making a Klondike style solitaire game, and I am trying to load a string into a 3D array. I am representing the "Tableau" with a 3D array (we haven't gone over structs yet). I want to represent the spaces which don't have cards with the word "empty". I'm not...

Ofcourse we can write the equations for blocks on a single fixed pulley taking the tension upwards and weight as downwards and then equating according to the acceleration. Can we write equations for the string (massless or with mass)?

I understand that suitable compactified strings in AdS correspond to conformal field theories (w/o gravity) living on the boundary space. What I do not get is the exact relationship between non-perturbative gravitational phenomena in the bulk and the CFT. All what I have seen are...

There is a spaceship situated orbitting a black hole at x million miles. We have an exactly x milllion mile long string (perhaps a bit longer) Lets not call it a string, but a flexible steel cable instead. Now, we tie a metal ball at its one end, and project the ball towards the black hole...

Could someone give me a short summary(if possible) of how discovering matter is made of vibrating energy will give explanation to all four fundamental forces?

I mean we really don't know what they are, right? We just know they can be positive or negative, north or south, but we really don't know why they exist. Will string theory give a definite answer to this? And also gravity. Will it confirm Einsteins theories?

Dear forums Hello. I teach physics, and whilst I think that my knowledge is fairly sound, once every now and I then I encounter something which baffles me like so... In a simple demo of circular motion, a rubber bung is whirled around the head in a horizontal plane. If the bung is...

Not sure if this is a topology question but here goes. Imagine an infinitely long piece of string and I cut it in half with a pair of scissors. Both pieces are still infinitely long but I'm now stood at the ends of infinitely long strings, how can I be at the end of something with infinite length?

Homework Statement "Vibrato" in a violin is produced by sliding the finger back and forth along the vibrating string. The G-string on a particular violin measures 30cm between the bridge and its far end and is clamped rigidly at both points. its fundamental frequency is 197Hz (a) how far...

Homework Statement Sound Wavelength From String During a concert a pianist hits a key that sets up a standing wave in a piano string that is vibrating in its fundamental mode. The string is 0.5 m long, has a mass density of 0.002 kg/m and is held under a tension of 120 N. What is the wavelength...

A rod (mass M, length L) hinged at point X. End Y is attached to X by an elastic string passing over a pin P, the natural length of the string is L. P is a distance L from X. Elastic Modulus of string: (1/4Mg) Refer to GPE to X and prove that total PE is: (1/4)MgL(1-cosθ-2sinθ) and find...

Can anyone explain to me what is string theory mathematically?

Please help me, I'm so bewildered it's not even funny. Does the frequency only depend on the source? This all seems so paradoxical to me...for example: An 100 Hz oscillator produces a wave on a rope with a wavelength of .1 meters. If I increase the tension of the rope by sticking a weight at...

The vibration in a string is caused by the tension force on point masses inside the string : The tension force itself results from "the net electrostatic attraction between the particles in a solid when it is deformed so that the particles are further apart from each other than when at...

It's really difficult as a layman trying to find out who is right and wrong in this debate as far as string theory. I find it kind of hard to believe that string theory is just simply completely wrong and has no relevance whatsoever to reality. After all so many theorists and so many papers...

Hi. I am fairly new to physics. I have recently read the first half of a book by Michio Kaku called “Beyond Einstein”, and I am really struggling to get my head around the superstring theory. The superstring theory seems illogical for the following reasons... 1. Nature demands symmetry. So...

Homework Statement Two blocks A and B with respective masses m_{A} and m_{B} with respective masses m_{A} and m_{B} are connected via a string. Block B is on a frictionless table, and block A is hanging at a vertical distance h from a spring with spring constant k that is at its equilibrium...

Now obviously String Theory has been responsible for some valuable research, and even if the theory were completely disproven (although I don't see how; my understanding is that it is still too vague in it's predictions and descriptions to be proven or disproven conclusively). But String Theory...

(I hope this is the right section). For those who play guitar, you might have noticed that plucking the open 1st string (E) causes the 5th (A) string to vibrate. Why is that? It doesn't happen with any other string/note that I'm aware of. I'm sure there's a physical explanation for it. :confused:

Can Loop Quantum Gravity and String Theory coexist? What if String theory was correct in its description of matter and 3 of the 4 forces, with the only difference from modern M theory being that there is simply no real particle called the graviton, and instead, gravity is as is described by LQG...

Hi everybody, let's assume the Higg's boson exists. If I understand String theory correctly (and I understand very little of it), then Higg's particle - just as any other particle - can be expressed as a particular vibration state of a string. If I understand Higg's theory correctly, then...

Each year, the annual String conference provides us with a kind of snapshot of the field as it is today. The lineup of invited speakers and the titles of their talks give an idea of the current activity and interests of string researchers. This year Strings 2012 is in Munich and starts on...

Homework Statement I am making a very, very simple program that takes in the date (of type string) from the user in the form DD/MM/YYYY. It then confirms whether or not the date is legitimate or not. For example, 09/07/2012 is valid, but 09/17/2012 is not valid. My program compiles...

I noticed that in quantum physics, an elementary particle has no dimensions, and is point like, but in string theory has one dimension. Why is this?

From what I understand, the Higgs Boson was the last missing piece of the Standard Model (12 indivisible particles, 4 forces). Now that the Standard Model is complete, has String Theory been disproved? Is there a conflict between the Standard Model and String Theory?

suppose a metal ball is hanging by a string and there is another string is hanging at buttom of the ball if you pull buttom string very fast which of strings (up and buttom) will be cutten ?

Say we have a guitar with electrical pickups near each end of one string. Say this guitar string is ideal in that it looses no energy to any form of "friction". Say the electrical pickups can act to both remove and add energy to the guitar string in the two dimensions perpendicular to the...

Homework Statement In attached figure, a closed tube is placed near a string that is fixed at one end and has a weight attached to its other end. When bridges A and B are positioned at the points shown,plucking the string between A and B causes the tube to resonate at its fundamental...

This may be a silly question since i am relatively new to the string theory. While going through a quantization of the bosonic string , I see a tower of states appearing corresponding to different modes of excitations of the bosonic string. Now I was trying to figure out how this whole machine...

Homework Statement The differential equation describing the motion of a stretched string can be written \frac{\partial ^2 y}{\partial x^2} = \frac{\mu}{T} \frac{\partial^2 y}{\partial t^2} μ is the the mass per unit length, and T is the tension. (i) Write down the most general solution you...

The 3rd harmonic on a piano string occurs when a 45.0 cm wave is produced. How long is the string. This question is really confusing can i get some leads to help me out please and thank u

Homework Statement A body of mass 1.00kg is tied to a string and rotates on a horizontal, frictionless table. If the length of the string is 40cm and the speed of revolution is 2.0m/s, find the tension of the string. Homework Equations a = v^2 / r f = ma v = 2∏rf Thanks :)

A long time ago, physicists thought that only a small class of quantum field theories (QFT's) makes physical sense - those which are renormalizable. But then gradually it became accepted (Weinberg was the most influential figure in that regard) that QFT does not really need to be renormalizable...

I like to think myself as adequately familiar with the concept of String Theory and it's basic fundamentals, But I'm wondering if string theory offers explanations to the currently unexplained such as universal expansion, quantum Entangelment, radio active decay, why virtual exist, etc? Or does...

Homework Statement Hi Can anyone please help with this question? A light elastic string AB has natural length l and modulus of elasticity 2mg. Another light elastic string CD has natural length l and modulus of elasticity 4mg. The strings are joined at their ends B and C and the end A...

Homework Statement Hi Guys I obtained a slighty different answer. Can anyone kindly verify where I am going wrong? The question is stated thus: A simple pendulum is of length 0.5m and the bob has mass 0.25kg. Find the greatest value for the tension in the string when the pendulum is set...

If String Theory explains/"leads to gravity, how does it not make predictions? String Theory "predicts" gravity. It can explain gravity and it explains "small" structures. If String Theory includes these two topics shouldn't it predict what happens when Quantum Gravity becomes non-negligible...

Homework Statement a 50m length of string with mass 0.0175 kg has waves traveling at 112 m/s. There is a mass attached to the string, 0.45 kg that is creating a 4.41 N tension. What is the frequency of the string vibrator? Homework Equations v=f*λ f= [√T/(m/L)]/2L The Attempt at a...

Hi, I'm new to Bash scripting and I need some help with this: I need to echo only a specified range of words from a string based on index; so for example if I had: a="hello how are you today" Is there a way to echo only "how are you" by specifying the index 2 to 4? (in one line...

I admit I don't know anything about string theory (nobody really does at an undergraduate level) but it sounds interesting and seems like something challenging. I am majoring in physics and maths but I am getting to the point in my undergraduate studies where I can begin to specialize more in my...

Homework Statement Consider an elastic string of length L whose ends are held fixed. The string is set in motion with no initial velocity from an initial position u(x, 0) = f (x). Assume that the parameter alpha = 1. Find the displacement u(x,t) for the given initial position f(x) The Attempt...