Dimensions Definition and 1000 Threads

Homework Statement if x_{1}= \begin{pmatrix}2 \\ 1 \\ 3\end{pmatrix} x_{2}= \begin{pmatrix}3 \\ -1 \\ 4\end{pmatrix} x_{3}= \begin{pmatrix}2 \\ 6 \\ 4\end{pmatrix} (i) show that x1,x2 and x3 are linearly dependent (ii) show that x1...

in M Theory. The concept seems like a bit of mathematical trickery to me. If you come up with enough variables, you can ultimately model any logical system without having much insight into the system's fundamentals. I'm not dissing the theory or anything. Basically I don't understand it well...

Homework Statement Hello, I am having some trouble with the two questions below: 1) The University of Maryland's mascot is a terrapin (a snapping turtle). It is represented on campus by a bronze statue in front of the library named Testudo. Unfortunately, students rub his nose for luck on...

Hi, I am also having trouble with the hockey puck question. A hockey puck rebounds from a board as shown in my diagram. The puck is in contact with the board for 2.5 ms. Determine avg acceleration of the puck over the interval. Vi = 26 m/s Vf = 21 m/s I tried the cosine law but I keep...

Maybe someone could inform me a little on what I'm talking about, because, honestly, I have no idea. If 11 dimensions=1 string theory -> 10 dimensions=5 string theories, is it possible to derive(right word? maybe) more string theories using lesser dimensions? Thanks. Even a yes or no answer...

Homework Statement Use Coulomb's law to determine the magnitude and direction of the electric field at points A and B in Fig. 16-57 due to the two positive charges (Q = 4.0 µC) shown. The Attempt at a Solution Basically, I'm completely lost. I've applied Coulomb's law to find the...

Homework Statement X and Y are dimensionally different. (They have different units.) Select ALL the physically meaningful operations. State which are true or false 1. X/Y or X*Y 2. X+Y or X-Y 3. e^(X/Y) or e^(X+Y) 4. X^2 +Y^2 or X^X + Y^Y 5. X^2 or Y^2 6. X^(1/3) or Y^(1/3)...

Homework Statement Homework Equations Fe = (kq1q2)/r^2 The Attempt at a Solution So for part A and B what is the best way to go about doing this? Could I find the distance between the charges and just use coulombs formula?

Homework Statement Two particles with masses 2m and 3m are moving toward each other along the x-axis with the same initial speeds v. Particle 2m is traveling to the left, while particle 3m is traveling to the right. They undergo an elastic, glancing collision such that particle 2m is moving...

Through a period of 60 years we developed quantum physics that enables us to imagine far beyond the capacity of an ordinary human mind. Quantum physics developed several String theories that were united in creation of M-Theory. M-Theory invovles 11 dimensions including the 4 dimensions that...

Topological Strings = 3 Superstrings = 10 Bosonic strings 26 Tensionless strings = arbitrary Do you know of any others that could fit in other dimensions not listed above?

Is it true that the existence of extra dimensions can lower the unification scale to the GeV scale? Does this mean that the LHC would be in range to detect a unification of couplings if this were true?

Hi everybody, it's my first post on here but as i seem to have hit a brick wall with my work I'm hoping somebody might be able to help me :) Homework Statement I'm looking at how the Planck scale is reduced in higher dimensions (ADD theories) and I've managed to reproduce an expression...

Why only three "non curled up" spatial dimensions? Is there a reason (inherent in the theory) that string theory describes 10 spatial dimensions with 7 of them curled up rather than having 8 or 3 curled up? In other words, is this curling up a consequence of other parts of string theory, or is...

Hi guys, I'm reading about unification of gauge couplings in the presence of extra dimensions but I'm coming unstuck in my understanding of what a Kaluza-Klein mode/excitation/tower is. I've looked ont he net and in string theory books but have been unable to find mcuh that is helping my...

Hi, Let's say I have two points: Pa = (0, 0, -30) Pb = (-2.5, -2.5, 7.5) and I want to find the X and Y values for a third point on this line whose Z value is 30: Pc = (X, Y, 30) How can I achieve this? My math is not very great and I'm applying this to a computer program. So...

This is my last annoying post here, probably. :) Homework Statement I have a curve \alpha: I \rightarrow \Re^3 parametrized by arclength. \kappa(t) \neq 0 for all I. Given the surface \psi (s,t) = \alpha (t) + (s-t) v(t), where v(t) = \frac{d \alpha}{dt}, t is in I, and s > t, I want to...

Homework Statement http://hypertextbook.com/physics/mechanics/momentum-two-three/an-elastic-collision-in-2d.pdf Homework Equations P = MV P= (r,θ) p'=mv' m1v1 + m2v2=m1v1' +m2v2' The Attempt at a Solution (2.00kg)(13.42 m/s) + (1.00kg)(12.73 m/s) = (2.00kg)(v1')+ (2.00kg)(21.95...

I watched astrophysical lectures by a scientist on the internet, and he claims that there are a total of twelve dimensions of space and time. Inlcluding "hyperdimensional" metaphysical universes and "spiritual" realms of being that are non-physical, and bear non-physical conscious...

Please could someone help me with this question, thank you. Find dim[Ker(D^2 -D: P_3(F_3) ==>P_3(F_3))] Where dim is dimension, Ker is kernal D is the matrix 0100 0020 0003 0000 D^2 is the derivative of D is it equals 0020 0006 0000 0000 And F_3 is the field subscript3...

Hello, If there is an oposite dimension to ours, does that mean that there would be an oposite me? If it does, does that mean that if I was thinking of the oposite me would the oposite me be thinking about me? Or would he be doing the oposite of thinking about me? Sorry if it sounds like a...

1. Variables Given a generalized basis in three dimensions: e_{1},e_{2},e_{3} and the standard Kronecker delta \delta_{ij}, and using Einstein summation. With the vector \textbf{x},\textbf{y},\textbf{z} I'm trying to simplify this problem: 2. Problem \delta_{il} . \delta_{jm} . x_{j} 3. My...

The Larmor formula is: P=\frac{\mu_0 q^2 a^2}{6\pi c} When I checked the units of this, I got [kg m^2 s^-1]. If it is in watts, shouldn't it be [kg m^2 s^-3]? I was pretty thorough in putting everything in SI units. \mu_0 is N/A^2 or kg m s^-2 A^-2. q^2 is C^2 or A^2 s^2 a^2 is m^2...

Any models worth checking out that do not rely on small curled up dimensions? And by large dimensions I don't mean 1mm, I mean all dimensions equally large.

Hi there, I'm new to this but trying like hell to figure the basics of this out, (as I did a while back but failed, then went off and left it.) and was wondering if this is why there's 11 dimensions : 1. Height 2. Width 3. Depth 4. Time Then we move onto the stuff that causes many of us...

M-theory, the latest version of string theory, posits 11 dimensions (ten space dimensions, one time dimension). Earlier versions posited ten or fewer dimensions. Brian Greene and other string theory proponents envision the first three "extra" space dimensions (beyond the three space...

Hello, I remember that I heard something about the curse of dimensions when discrimitating between samples with high dimensional parameters. Therefore a sample might have the property vector (x1,x2,...,xn) and one could define a measure of distance (euclidean, manhattan, ...) to judge how...

Homework Statement Find the dimensions of the rectangle of largest area that can be inscribed in a circle of radius r. Homework Equations (x-a)^2 + (y-b)^2 = r^2 max area = 2x(2y) = 4xy The Attempt at a Solution (x-a)^2 + (y-b)^2 = r^2 = y=r-(x-a)+b I then plug...

Homework Statement Assume an elastic collision (ignoring friction and rotational motion). A queue ball initially moving at 4.3 m/s strikes a stationary eight ball of the same size and mass. After the collision, the queue ball’s final speed is 2.3 m/s . Find the queue ball’s angle with...

This applies to the small extra dimensions. The rolled-up compact kind that we wouldn't see if they were there. Paul Steinhardt has just posted a paper proving no-go theorems that exhibit an impressive degree of incompatibility between compact extra dimensions on the one hand versus the...

As far as i know, a dimension is basically spatial parameters in which "stuff" can move. I think that what bugs me the most about physics is that we know the what but not always the why... obviously this is not anyone's fault especially because finding out why things are the way they are is much...

http://folk.ntnu.no/stoylen/strainrate/mathemathics/ This page shows how to find shear strain in three dimensions. I understand how they found the shear strains as x and y components from dividing the change in length by the original length. But from the line "From the figure, it is...

If V and W are 2-dimensional subspaces of R4 , what are the possible dimensions of the subspace V intersection W? I am new to subspaces, so I have no clue to this question. Help guys! Options: (A) 1 only (B) 2 only (C) 0 and 1 only (D) 0, 1, and 2 only (E) 0, 1, 2, 3, and 4

Hi everybody, I want to tackle the study of the physics of new dimensions: theoretical and phenomenological (Dark matter) aspects. Could you please point to some interesting books/articles ? Thanks in advance.

Homework Statement A train at a constant 79.0 km/h moves east for 25 min, then in a direction 37.0° east of due north for 18.0 min, and then west for 54.0 min. What are the (a) magnitude (in km/h) and (b) angle (relative to north, with east of north positive and west of north negative) of its...

Homework Statement As an example of the manipulation of an electron beam, consider an electron traveling away from the origin along the x-axis in the xy plane with initial velocity v = vi. As it passes through the region x = 0 to x = d, the electron experiences acceleration a = ax + ay, where...

I need help in seven exercises of physics, I just don't know what do... I'd like you to do one or more exercises with it's process so that I can analyze somehow the process and learn how do to it, I have an exam tomorrow and I have to study.. here are the problems: 1) An artillery shell is...

:cool: I'm doing my doctorate dissertation on the determination of molecular dimensions. I alredy know avagadro's constant and can understand the science of it, but the math is very complex and difficult to understand.:confused: I also need to know the different experiments that can be used...

Im not sure if this is the proper area for this but when they say that there might be other dimensions that we don't no about are they referring to more than xyz? i mean how could something have another dimension, it seems weird to think about. Just looking for someone who has some insight on...

Homework Statement what are dimensions of [V]volume and [v] speed expressed as powers of length, mass, time. Homework Equations The Attempt at a Solution i thought of speed as miles per hour...but didnt come out right.

Hi. I'm looking at Berkovits' pure spinor formulism of string theory. I am a PhD student studying mathematics and so am having trouble with some of the physics behind the mathematics. Say we have V a 10 dimensional vector space and we pick an irreducible representation of Spin(V) - which is...

Homework Statement A soccer player kicks the ball toward a goal that is 16.8 m in front of him. The ball leaves his foot at a speed of 16.0 m/s and an angle of 28.0 degrees above the ground. Find the speed of the ball when the goalie catches it in front of the net. Homework Equations x =...

What is the true definition of our universe in terms of spatial dimensions? Should the definition of universe include higher spatial dimensions? Is the expansion of our universe causing gravity; if our universe wasn't expanding, would we have the natural phenomenon of gravity? Is the...

Question and Data What is the initial velocity of an object that rolls off a table and hits the floor below? Lab produced the following data: Table height: 86 cm Distance of object from table when it hits floor: 23 cm Relevant equations Instantaneous Speed: Vf = Vo + at [I think this is the...

Homework Statement A playground is on the flat roof of a city school, 6.00m above the street below. The vertical wall of the building is 7.00 m high forming a 1m high railing around the playground. A ball has fallen to the street below and a passerby returns it by launching it at an angle of 53...

My question seems rather simple, but I could't have the right answer. Hope you can help me about it. Thanks! Determine a convertion factor that, upon multiplication, changes an acceleration in miles per hour times second (mi/h*s) to meter per second squared (m/s^2).

A golfer imparts a speed of 30.3 m/s to a ball, and it travels the maximum possible distance before landing on the green. The tee and the green are at the same elevation. (a) how much time does the ball spend in the air? (b) What is the longest "hole in one" that the golfer can make, if the ball...

Homework Statement A ball is tossed from an upper-story window of a building. The ball is given an initial velocity of 8.00m/2 at an angle if 20 degrees below the horizontal. It strikes the ground 3s later. (a) How far horizontally from the base of the building does the ball strike the...

Homework Statement here's a picture of what the case is : http://img67.imageshack.us/img67/6425/imagevn8.png" if I drop a ball with the initial velocity is v at h. How do I find R here in terms of h? Homework Equations The Attempt at a Solution

Something seems a little weird to me: What are the dimensions of a generating functional, Z[j] -- say for real scalar field theory? Z[j]=\int\mathcal{D}\phi\,\exp\, i\!\int d^4x\left(\frac{1}{2}\partial_\mu\phi\partial^\mu\phi-\frac{1}{2}m^2\phi^2+j\phi\right) Also, what about mass dimensions...