Dimensions Definition and 1000 Threads

Homework Statement a ball of mass 2kg is traveling North with a Velocity 6m/s when it collides with an identical, stationary ball. after the collision, one of the ball moves with a velocity of 2m/s at an angle of 30deg east of north. find Velocity of the other ball. m1=2kg m2=m1 v1=6m/s...

Hello; I am curious about how many dimensions there are in physics. My physics teacher responded with '10 or 11'. -1 dimension: ? 0th dimension: Fixed point 1st dimension: Line 2nd dimension: Flat plane 3rd dimension: Object with depth on a flat plane. 4th dimension: 3-dimensional...

Hi, I have no knowledge of ST but have a probably simple question. I saw a program about how the extra dimensions of space in string theory are curled in on them selves. What I want to know is if they really are the same dimensions. Say for example if there are 11 dimensions and I would pick...

I'm wondering if the perception of spacetime as "3 dimensions of space and 1 of time" is a symptom of our inability to maintain an objective view on the matter. I believe the reason we separate them in our minds is because we seem to have some control over space but no control over time. But...

Homework Statement Consider a Cartesian coordinate system, with units measured in 1000 feet, and with the z = 0 coordinate plane lying on the ocean surface. Two ships A and B, moving at speed 250 feet/min, are located at (4,0,0) and (0,5,0), moving North (-x direction) and West (-y direction)...

Hi =D I was thinking about the physical units (g, m, s, K, J, A, V, etc). I know we got a thing in physics called dimensional analysis, so you analyse some variable that you know it depends on other variables and the two sides of the "equation" (I mean a equation with the proportional sign...

Hi everyone , this is my first time here :) My question is simple , if gravitation is basically a space distortion so it's fair to say that at least a fourth dimension exists , since a distortion must occur in higher dimension than the one of the concerned space . Is it correct putting it...

Hello all, I'm trying to design an efficient airfoil for a wind turbine blade. To be entirely honest, I'm not entirely familiar with this field of engineering; I mainly specialize with steam applications, so this design attempt is obviously a somewhat far cry from that! Yet I've been trying...

helloo! i'm trying to find the Green's function for the modified heat equation $u_t = t * grad(u) $ in n dimensions using scaling arguments. I know how to do this for the regular heat equation, by switching to polar coordinates and noticing that the equation and initial conditions are...

There is the possibility that spacetime has more than 4 dimensions, and that the additional dimensions are curled up not at the Planck scale but at some larger scale. There has been some discussion that if these extra dimensions exist, then the LHC might produce microscopic black holes (which...

hi everyone, i am no physicist so i only have a slight understanding of these matters. I just finished reading Greene's "elegant universe" and i understood that in "classical" string theories there are 6 compactified dimensions along with our familiar 3 extended spatial dimensions + time...

Homework Statement I've completed the derivation of the hypersphere volume for integer dimensions, and my solution matches what's on Wikipedia. How can I generalize it to fractional dimensions? Homework Equations The Attempt at a Solution Not a clue; my only guess at this point...

Im working through derivations of string equations of motion from the Nambu-Goto Action and I'm stuck on something that I think must be trivial, just a math step that I can't really see how to work through. At this point I've derived the equation of motion for the closed string from the wave...

Hey I have this plate, and as you can see it has 4 bolt connections and no other. When applying the load bending will occur in the plate. I am interested in making the diameter of bolt as small as possible. My problem is though that I only can see the shear forces in the plate. How can I...

Homework Statement Hi! This is from Physics for Scientists and Engineers, Vol. 6 by Tipler and Mosca. 44. Kepler's third law relates the period of a planet to its orbital radius r, the constant G in Newton's law of gravitation, and the mass of the Sun Ms . What combination of these factors...

String theory requires 9 spatial dimensions, M-theory 10. One followup to Verlinde's paper is this: http://arxiv.org/abs/1002.0488 Hidden symmetries for thermodynamics and emergence of relativity Liu Zhao (Submitted on 2 Feb 2010) Verlinde recently proposed an idea about the thermodynamic...

Homework Statement In the game of darts, the player stands with feet behind a line 2.36 m from a dartboard, with the bull's-eye at eye level. Suppose you lean across the line, release a dart at eye level 2.23 m from the board, and hit the bull's-eye. Find the initial velocity of the dart, if...

Edit*: problem solved. Thanks for the hint Dick.

it seems that the vector product between vectors in three dimensions is peculiar property of the three dimensional space

Homework Statement Two spacecraft from different nations have linked in space and are coasting with their engines off, heading directly toward Mars. The spacecraft s are thrust apart by large springs. Spacecraft 1, with a mass of 1.9 x 10^4 kg, then has a velocity of 3.5 x 10^3 km/h at 5.1...

If we start with minkowski spacetime in 4 dimensions and then add several curled up spatial dimensions attached at every spacetime point, then: I'll label a spacetime point as: (ct,x,y,z)[a1,a2,a3,..,an] where the bracketted coordinates are the 'curled' coordinates. - If we label the...

what problems are solved by the theory of 11 different dimensions instead of just 1-4 proposed in the m theory and string theory

How does one know that chemical, atomic, and nuclear reactions occur in three spatial dimensions? Why not four, or two, or negative pi, or sixty-seven dimensions? And yes, I know the last two are implausible.

Special Relativity vs. "Curled up" spatial dimensions To be more specific I mean the 3 familiar spatial dimensions not extra ones(unless I guess they are large enough for SR to be effective). Anyway, I was reading a book on Superstring Theory(Which is why I say not extra ones it proposed extra...

I took physics in high school many-many-many moons ago. Mr. Smith taught that molecules can only exist inside a three dimensional environment. Is that true?

What is the meaning of Living in a World having 3 Dimensions? As to the guy on the street, how is he affected by being tied to 3 dimensions? Can we make a simplified button list in language that a non scientist can understand?

a derivation of the formula for arc length is simple enough: given a function f[x], find the length of the arc from x0 to x1. lim(x1-x0)/n=dx n->inf x1 S=^{i=n-1}_{i=0}\sum\sqrt{(x+(i+1)dx-(x+idx))^2+f(x+(i+1)dx)-f(x+dx))^2} xo...

Strings live in 9+1 world, M, 10+1 one line of criticism is string theory is unable to account for the number of large and compactified dimensions, i.e 1 (line) large, 9 curled, 2 large (sheet), 7 curled, 3 large 6 curled (our world) all the way to 9 flat or 9 curled. Is there an a priori...

Hi, Im trying to work out the dimensions of the offset on a cam for a project. I know the travel of rod c, as well as the length of the connecting rod b, but I am not sure what the lenth of dimension a should be. I know this is probably simple maths (just pythagoras?) but I need to make sure...

Planck energy: E_P = m_P c^2 = \sqrt{\frac{\hbar c^5}{G}} Gravitational radius: r_G = \frac{r_s}{2} = \frac{G m_P}{c^2} Gravitational radius is equivalent to Compton wavelength: r_G = \overline{\lambda}_C \frac{G m_P}{c^2} = \frac{\hbar}{m_P c} Planck force is a constant in the Einstein...

Think about the dimensionality of a balloon with surface waves. Say these waves are of small amplitude compared with the radius of the balloon. Two coordinates label points on the balloon and a third labels radial position. Creatures who lived on the surface could make measurements that...

Holographic principle aside, I believe that there is no theoretical basis for a 3rd spatial dimension, only experiential, since we can see and measure depth, as well as height and length. From what I've read, however, all forms of depth perception require movement, or otherwise don't allow...

Dear guys, I want to understand the spinors in various dimensions and Clifford algebra. I tried to read the appendix B of Polchinski's volume II of his string theory book. But it's hard for me to follow and I stuck in the very beginning. I will try to figure out the outline and post my...

Hey there, I've just started learning quantum mechanics and I'm currently reading about gravity and higher dimensions. That is, I know so very little and would like to see if somebody could lend me some clarification . The uncertainty relation comes from the fact that matter waves in and out...

I am layman, so I can't find an answer on my own. Suppose, on low energies space is (locally) pseudo-euclidean with the number of spatial dimensions S and time timensions T In our universe S=3 and T=1 My question: is it possible to 'adjust' equations of GR and QM/QFT to the different S...

Iv'e scene the documentary about string theory and i just have a few questions about it.(laymen terms) : 1.How does string theory contribute to a unified field theory? 2.Is matter really made of "vibrationg strings"? 3.What does string theory actually mean or what has been the impact...

Homework Statement Find the flux of field \mathbf{F}=x\mathbf{i}+y\mathbf{j}+z\mathbf{k} across the portion of the sphere x^{2}+y^{2}+z^{2}=4 in the first octant in the direction away from the origin in three ways: a. using formula for flux when sphere is a level surface b. using formula...

Homework Statement Determine the dimensions of a rectangular box, open at the top, having volume 4 m3, and requiring the least amount of material for its construction. Use the second partials test. (Hint: Take advantage of the symmetry of the problem.) Homework Equations The...

Okay. My reason for posting this is that I need help actually formulating the 'math part' of it. I can get the right answer by 'inspection.' And from the way the book is written, I believe that is how the authors expect you to find it. But for self gratifying reasons, I wish to generalize...

As we know, Newton's Law of Gravitation is \[ {\mathbf{F}} = \frac{{Gm_1 m_2 }} {{r^2 }} \] and Coulomb's law is \[ {\mathbf{F}} = \frac{{Qq_1 q_2 }} {{r^2 }} \] We know from comparing the dimensions of the first equation that G, the gravitational constant, has the dimension \[ [M^{ - 1}...

Apologies if I've missed something fundamental - as I only have very little university Physics background (3 semesters). I've watched this old youtube video again out of curiosity: I don't think I fully understand it. This is what I have so far...

Homework Statement A worker pushed the Piano weighing 93N up a ramp into a moving van, pushing horizontally, parallel to the ground. The ramp extends 4m over the ground and 3m high. The top, sloped surface of the ramp holding the piano is 5m long. The worker exerts a force of 85 N. How much...

Having diffuclty understanding the concepts, etc. I did alright for one dimension, but now I am pretty lost. I have trouble knowing what to find and how to draw everything out. (Chapter 3, Cutnell & Johnson, 7th Edition). Does anyone have any recommendations on online outlines or even youtube...

Homework Statement A swimming pool has dimensions 34.0 m 9.0 m and a flat bottom. When the pool is filled to a depth of 2.30 m with fresh water, what is the force caused by the water on the bottom? I have the answer to this which is 6.90 x 10^6, however I cannot figure out the pressure on the...

Homework Statement http://carlodm.com/calc/123.png My question is: Why can't we use a scalar multiple like (3/8) PQ instead of using the midpoint formula twice (to get 3/8) ?

Is it possible to change: _______ distance = \/X2 + Y2 To: _______________ distance = \/X^2 + Y^2 + Z^2 And get the distance between a point in 3 dimensional space and a the point of origin, just as the first equation does in 2 dimensional space...

A glass is slid across a table top, goes off the edge and falls to the floor. The table is 0.860m high and the glass lands 1.53m from the edge. a)With what velocity did the glass leave the table top? b)What was the direction of the glass's velocity(degrees clockwise from the horizontal)as it...

questions in [ motion in two dimensions ] q. [ .. if you know the position vectors of a particle at two points along its path and also know the time interval during which it moved from one point to the other m can you determine the particle's instananeous velocity ? its average velocity ...

The airplane shown is in level flight at an altitude of 0.50 km and a speed of 150 km/h. At what distance d should it release a heavy bomb to hit the target X? -I tried using x-x0=(v0)(cos(theta))t; and then solving for t with another equation but that does not give me the correct answer...

Hey I'm having problems trying to integrate my function func1 in MATLAB. Really don't know where I am going wrong so would really appreciate if anyone could help. The code I'm using is below, thanks: Function Mfile: function [ f1 ] = func1( E, Delta, kB, Temp ) %func1: calculates...