String Definition and 1000 Threads

Homework Statement I'm going through the derivation here starting on page 16. This image adds some context: . Generalizing their result to the i'th particle they find the extended distance between two masses being ##\Delta l= \frac{(y_i-y_{i-1})^2}{2a}## Then since the potential energy is...

Homework Statement (I have dropped the hats on the ##\alpha_{n}^{u}## operators and ##L_{m}##) ##[\alpha_{n}^u, \alpha_m^v]=n\delta_{n+m}\eta^{uv}## ##L_m=\frac{1}{2}\sum\limits_{n=-\infty}^{\infty} : \alpha_{m-n}^u\alpha_{n}^v: \eta_{uv}-\delta_{m,0}## where : denotes normal-ordered. Show...

Homework Statement A 1.5 kg ball is tied to a string that is .75 m long and whirled in a verticle circle. A) Find the tension in the string at the top of the circle B) Find the tension in the string at the bottom of the circle Homework Equations Fc=mac ac= v2/r The Attempt at a Solution A)...

Homework Statement I'm having trouble understanding an example given in K&K's Intro to Mechanics textbook. 'A string with tension ##T## is deflected through an angle ##\theta_0## by a smooth fixed pulley. What is the force on the pulley'. I don't understand how (in the first picture) they...

Is it possible to associate electric and magnetic fields with the vibrating string that is thought to represent a photon in string theory? Thanks!

Homework Statement A child is swinging a .325 kg ball at the end of a .74 m long string in a vertical circle. string can withstand a tension of 12 N before breaking. What is the tension in the string when the ball is at the top of the circle if its speed at that point is 3.4 m/s? Homework...

Lightcone gauge is ##X^u=\tau=1/\sqrt{2}(X^0+X^{D-1})## (1) The mode expansions are: My book says 'it is possible to solve for one of the oscillators in terms of all the others' with this relation. What is a oscillator? Is this any of the ##X^{D}## coordinates, what exactly does ##n##...

Are there anything new in String theory?

Homework Statement A 5kg ball is swung in a circle of radius .5 meters at a constant speed of 2 meters per second, how much work does the centripetal force do as the ball does once in a circle?If the ball were pushed the same distance as the circumference of the circle with a force equivalent...

Homework Statement the velocity of a harmonic wave in a strung-wire is 1550m/s and the wave's frequency is 740Hz there are two oscillators (?) in the wave called A and B such that B is 2m further ahead of A in the direction of the wave's travela) calculate the phase difference between A and B...

Homework Statement As shown in Figure 1, two objects A and B of the same mass m are moving on a horizontal plane without friction along x axis. The two objects are connected by a string of length l. The mass of the string is negligible, and the length is constant. At time t = 0, A is to the...

The length of a string is 1328 cm. It is held fixed at each end. The string vibrates in eight sections; i.e., the string has eight antinodes, and the string vibrates at 97 Hz. Find the wavelength and fundamental frequency. I have no clue, anything helps! Thank you!

Homework Statement A small wooden block with mass 0.800 kg is suspended from the lower end of a light cord that is 1.60 m long. The block is initially at rest. A bullet with mass 0.0132 kg is fired at the block with a horizontal velocity v-_i. The bullet strikes the block and becomes embedded...

Homework Statement In an effort to rev up his class, Mr. H does a demonstration with a bucket of water tied to a 1.3-meter long string. The bucket and water have a mass of 1.8 kg. Mr. H whirls the bucket in a vertical circle such that it has a speed of 3.9 m/s at the top of the loop and 6.4 m/s...

Homework Statement Block A, with weight 3w, slides down an inclined plane S of slope angle 36.9 degrees at a constant speed while plank B, with weight w, rests on top of A and is attached by a cord to the wall. If the coefficient of kinetic friction is the same between A and B and between S...

Hi, guys. For my project this week I have to code a cipher, and I am just getting used to what, what with the code. The problem I am having is that I have assinged my key and instered that into the repeat function but I only get one output of maths and not seven, why is this? program Jason...

Homework Statement Suppose a string is 0.50 m long, it has a mass per unit length of 1.2 g/m, and it is under a tension of 52 N. What is the frequency of the second mode of this string? Express your answer in the SI unit for frequency? Homework Equations f = Vs/2L Vs = sqrt (F/μ) The Attempt...

I don't know how to display what the string you see in the array. Do I need to put something in the paint method? It's annoying because my book and everywhere I look only show examples using integers and not strings. This code is in the init method. I can't find out where to display the "dog"...

I have a decent background in physics, but something that has always confused me is how to think about how the tension of the string in a tennis racquet affects how the ball leaves the strings. For example, the traditional lore in tennis is that tauter strings will give more control, whereas...

Are interpretations that are non linear with respect to the wave function (eg. GRW, transactional) compatible with string theory?

Homework Statement Suppose we listen to the sound of a vibrating string with a pickup that is sensitive to the motion at a point 1/3 of the string's length from one end. Which statement is true? A.) We will be able to hear all of the modes except the third B.) We will not be able to hear the...

Homework Statement How can I store String s in X x_obj [] = new X [100] ;2. What I tried I tried x_obj [0] = s; But it didn't work. I know there are easier ways but this is how I have to do it. Thanks in advance

Hi. I've been searching for some description of the following. Something that will explain it and perhaps even some maths about it. Take a rod or a stick and tie a string around its middle. Hang it so the string is unwound, still. Start turning the rod so the string twists around. Keep...

Homework Statement http://tinypic.com/r/10f5ni8/9 http://[PLAIN]http://i66.tinypic.com/10f5ni8.png Homework Equations I have a problem understanding this problem. It asks for the velocity of block A when block B is moved 300mm/s to the right. The equation for the cord length is given as...

Homework Statement A ball of mass 1.00Kg is attached to a loose string fixed to a ceiling.The ball is released from the rest and falls 2.00m,where the string suddenly stops it.Find the impulse on it from the string. Homework Equations .[/B] Kinematic equations...

Hello everybody! I hope you are having a great day ! My question: is the strings theory a REAL theory ... is it really the final answer to the relationship between relativity and quantum mechanics! ? [emoji54]

If input is 2: call int calculate(string exp) function. This function will return the computation of a string expression (exp). For example: calculate(“54321+222”) will return 54543 calculate(“120*20”) will return 2400 calculate(“235/3”) will return 78 calculate(“356-32”) will return 324My code...

Homework Statement Given Ma = Mb =Mc and muk between c and the surface is 0.30 Homework Equations (rope length) = constant Maaa = Mag - T Mbab = Mbg - 2T Mcac = T - (mu)Mcg The Attempt at a Solution The equations I came up on my own and the answer key did as well. The problem is I also need...

Homework Statement So I don't really understand what the professor means by "show why the displacements y(x,t) should satisfy this boundary value problem" in problem 1. Doesn't that basically boil down to deriving the wave equation? At least in problem 2 he says what he wants us to show...

Hello, I am aware that there are specific oscillatory patterns than can form on on a string. These patterns are called normal modes and represent standing waves. Each standing wave has an associated frequency f which indicates the speed at which the string's points are moving up and down...

It seems that the latest data out of CERN suggest a mass of the Higgs Boson that is smack in the middle of what would be suggested by parallel universes/string theory and SuSy. Do you think Edward Whitten, Savas Dimopoulos, and probably others could get together in a room to unify these two...

Homework Statement Homework Equations F = mw^2r [/B]The Attempt at a Solution For part a, I can't get the constant of half with the tan a I am getting tan a = w^2l/g

Does the length of a string depend on its energy, or does its energy depend on its length? Similarly, does the area of a d brane depend on its energy, or does its energy depend on its energy? Are these stupid questions?

Dear all, recently I'm reading up some string/M-theory, especially the role of branes, because I'm writing a popular science book in Dutch. Every textbook states the issues one encounters when you try to quantize p-branes for p>1, as is discussed e.g. here...

can string theory reproduce hawking radiation in non-extremel black holes in 4D? i.e physically realistic black holes. do they exactly match hawking's calculations? what is the interpretation of hawking radiation in string theory?

< Mentor Note -- thread moved to HH from the technical physics forums, so no HH Template is shown > A transverse wave on a string has an amplitude of 16cm, a wavenumber of 5.7m-1, and a frequency of 39Hz. What is the propagation speed of that wave? (a) 6.84 m/s (b) 39.2 m/s (c) 43 m/s (d) 6.24...

Homework Statement http://i.imgur.com/sWZS9vQ.png Homework Equations P=½ √μF ω2 A2 The Attempt at a Solution How is the equation related to the wavelength? Thanks

1. Part One: A mass M1 = 30 kg is suspended by a light string from the ceiling of a lift of mass M2 = 300kg. If the lift accelerates upwards at 1 m/s2, what is the tension in the lift cable and in the string? (g=9.8 m/s) Part Two: If the string breaks when subjected to a tension of more than...

Homework Statement I'm in need of a more conceptual answer, rather than numerical. Say you have a block on a horizontal frictionless table (block 1). Then you have a string tied to block one and strung over a pulley that is at the right end of the table (the pulley has mass). On the other...

Homework Statement Let's have a disk of mass ##m## and radius ##a## 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...

Could someone explain or point me in the right direction on how string theory explains the leptons? TIA, Kevin

Homework Statement A mass m is suspended by a light elastic string. When the mass remains at rest it is at a point 0, which is a distance a + b below the point from which the string is suspended from the ceiling, where a is the natural length of the string. The mass is pulled down a distance h...

Homework Statement The tension in the string is 90N; the string is 60cm long and has a weight of 34.44g. What is the speed of the wave on the string? Answer: 396 m/s Homework Equations v = √ T / (m/L) The Attempt at a Solution v = √ 90N / (0.0344kg/0.6m) v = 39.6 m/s Huh? This looks like it...

I was doing some reading on String Theory...I'm not a scientist, but i enjoy it (so forgive me if my question is stupid) and i was wondering: Being time a dimension, could it be the dimension the strings exist in? And interaction between all particles and all forces determine how they vibrate...

Homework Statement A long rope with mass m = 10 kg is suspended from the ceiling and hangs vertically. A wave pulse is produced at the lower end of the rope and the pulse travels up the rope. (a) Explain why the speed of the wave pulse change as it moves up the rope; does it increase or...

Homework Statement So referring to this lab , http://static3.mbtfiles.co.uk/media/docs/newdocs/international_baccalaureate/physics/824297/html/images/image12.pngIn this lab you are holding the plastic tube and twirling it to make the small mass spin in a circle. Keep in mind there is a mass on...

Hello, I have a question about the the difference between mathematical physics and theoretical physics in general and about the difference between the MSc Theoretical and Mathematical Physics courses at Edinburgh in particular. I am planning to apply, however I am not sure which of the two...

Two masses, m1 and m2, are attached by a light string of length D. Mass m1 starts at rest on an inclined plane and mass m2 hangs as shown. The pulley is frictionless but has a moment of inertia I and radius R. Find the Lagrangian of the system and determine the acceleration of the masses using...

I have read the description of electrons as standing waves based on an analogy with a string vibrating at its natural frequencies: thus the different quantum levels are akin to the tones or harmonics of the string, right? So far, so good, but then I have seen contradictory complementary views...

Homework Statement How many strings of length 10 contain either five consecutive 0s or five consecutive 1s? Homework EquationsThe Attempt at a Solution So this problem isn't too bad, and I have a pretty good idea of how to solve it. However, I am not sure whether the problem is referring to...