Dimensions Definition and 1000 Threads

Homework Statement Solve the time independent Schrodinger equation for an electron in a 2-D potential well having dimensions Lx and Ly in the x and y directions respectively.Homework Equations d^2Y/dx^2 + d^2Y/dy^2 + 2m/h^2*EY = 0The Attempt at a Solution Y(x) = A exp(jkx) + B exp(-jkx) I'm...

A fire fighter directs a stream of water from a fire hose into the window of a burning building. The window is 20.0 m above the level of the nozzle and 60.0 m away. The hose produces a jet of water at a constant nozzle speed of v0 = 30.0 m/s. The fire fighter can control the angle θ0 that the...

Homework Statement A ball is hit by a golfer. The angle is 28 degrees, the velocity of the projectile is 16.0, the distance is 16.8m on horizontal. What is the velocity before impact on the ground of the ball? Homework Equations The Attempt at a Solution

Can we derive the equation , F = (Gm1m2) / r2 using dimensional analysis?

In terms of physical dimensional size, what are the measurements a black hole must fit in order for it to actually reverse the expansion of the universe and cause a total suction of the space-time fabric that constitutes our universe, in its current position? I will appreciate a profound...

Homework Statement A hot-air balloon is rising straight up with a speed of 2.4 m/s. A ballast bag is released from rest relative to the balloon when it is 9.6 m above the ground. How much time elapses before the ballast bag hits the ground known data y direction vo = 2.4 m/s a =...

Fans claim that Michael Jordan is able to jump and remain in the air for two full seconds from launch to landing. Evaluate this claim by calculating the maxium height that such a jump would attain. For comaprsion, Jordan's maximum jump height has been estimate at about one meter. Y=1meter...

A golfer imparts a speed fo 26.0m/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...

There are 'four' experimentally proven dimensions. Anything and everything must be defined by 'four' dimensions. It doesn't make sense to me to say "An Object exists in two dimensional space" or "Three dimensional." To mean there is one dimension, what everything exists in, defined by...

Homework Statement If an arbitrary intial state function for a particle in a box is expanded in the discrete series of eigenstates of the Hamiltonian relevant to the box configuration, one obtains: \psi(x,0) = \Sigma^{\infty}_{n=1}b_{n}(0)\varphi_{n}(x) If the particle is free, we obtain...

I know that the compactified additional dimensions is the standart explanation, but the way I have thought of this is: The reason we can't see these dimensions, is that light fotons are bound to the 3rd D, and can't escape. Just like waves at the ocean can't escape its 2D surface. and neither...

Probably a stupid question but... I have a device with a bolt that is designated #6-32 UNC. I need to drill a hole in a surface to for this bolt to fit into. How big should this hole be? If the material I am going to be threading the bolt into is plexiglass do I need to thread the hole I...

Homework Statement Microwave oven I. The glass window isn't important to the microwave oven's operation, but the metal grid associated with that window certainly is. The grid forms the sixth side of the metal box that traps the microwaves so they cook food effectively. What is the approximate...

Greetings, I'm trying to design a system that creates a thermal gradient in 2 dimensions through several layers of very different material (copper, acrylic, and ice). I was wondering if there's some cheap software available or even some kind of shareware out there that could give me at least...

Hi, I have a question about extra dimensions. I don't understand what means that a dimension is compactified. Thanks a lot! Sorry it's the wrong forum. It belongs to Beyond the Standard Model , but I don't know how to remove it!

I recently read an article(http://www.newscientist.com/article/mg20327231.900-beyond-space-and-time-5d--into-the-unseen.html) that said that gravity in the fifth dimension could be electromagnetism, but wasn't his math flawed? I seem to recall there being something wrong with this idea.

A rectangular block has dimensions 2.9cm x 3.5cm x 10.0cm. The mass of the block is 615.0 g. What are the volume and density of the block? how do you do it?

according to string theory, gravity got the ability to escape the D-brane of witch all matter is bound. The reason is that the boson carrying the gravity is a loop-string, with no open ends linking to the brane.. this theory should explain why the gravity is so much weaker than the other forces...

I am simply trying to understand why dS space has a signature (4+1) ? Good old familiar Minkowski space is of course, (3+1), crystal clear. What is the role of the extra spatial dimension in dS ? Why should the manifold be 5-D ?

Can there be a place(?) where only 5 dimesional object are allowed? Or would there always be the need for a 4 dimensional surface of the 5 dimensional obect? If you'll always need to be able to subtract a dimension (the edge of a 2d plane is a 1d line and the end of a 1d line is a 0d...

Hi all, I am not a physicist. Some engineer friends of mine and I have a question about special relativity in two dimensions. To set it up, there are 2 lights floating in space parallel to the x-axis and a spaceship is traveling at .8c flying parallel to the y-axis towards the midpoint of...

Ok, I often hear that things become more easily understood in higher dimensions. I also hear that it is easier to express them in math than with words. But what does equations that express higher dimensions look like? Is it something as simple as (x,y,z,w)? I might be over thinking this far...

I'm working on a visualizer of sorts for a system: x_{n+1} = sin(a y_n) - cos(b x_n) y_{n+1} = sin(c x_n) - cos(d y_n) with a,b,c,d \in [-2.5, 2.5] So for whatever initial (x_0,y_0) I give the system, I know the next iteration will have both x and y between -2 and 2, and that will be...

I'm hoping someone is willing to help me with this question. Time is well explained when observed at point between absolute rest and c. The faster an object travels through the dimension of space, the slower that object travels through the dimension of time. Fair enough. Does this...

What experiment could determine whether our universe is fractal?

Homework Statement Object 1: m1=1.9x10^4 kg v1'= 972 m/s [E5.1*N] Object 2: m2=1.7x10^4 kg v2'=944 m/s [E5.9*S] Determine their original speed when they were linked together. Homework Equations Pti = Ptf m1v1 + m2v2 = m1v1' + m2v2'

So, I've got a problem understanding the "algorithm" for changing variables in a more-than-one-dimensional integral. For the two-dimensional case, I've got a specific problem that I'm looking at: \int^{a}_{0}\left(\int^{2a-x}_{x}\frac{y-x}{4a^2+(y+x)^2}dy\right)dx which I assume is an...

Homework Statement Dimensions: These derivations are not correct ( as stated by the book) I'm just reading my textbook at the moment and I saw this example ( So I don't have work for it myself by the book shows all the steps). ***√[L]/[L/T^2] =√[T^2] Homework Equations The...

Well, it's more of a general inquiry than a specific question, but this looked like as good a place as any to bring it up. Can a quantity have dimensions NOT of the form: [L]^{x}[M]^{y}[T]^{z}, where x, y and z are real numbers? This includes two primary cases as far as I can see. One is...

I'm beginning to study multiple dimensions, and I guess the first step after the x, y, z coordinate system is to study how the TESSERACT is formed. How is this weird 4 dimensional cube formed? I've seen videos and pictures of it, but I cannot imagine the 4th dimension. any advice?

Hey Everyone, So I've been working on some very basic QM mathematics. Basically I've worked out the wave equation for a particle in one dimension (briefly) like so: -\frac{\hbar 2}{2m}\psi"(x) + V(x)\psi(x) = E\psi(x) V = 0 for 0 < x < L ; (L = "Length" of the Boundary) =>...

waht caused compactification of the extra dimensions in the early universe?

It is my understanding that physicists hope to use conservation of energy in the LHC to determine if there are multiple dimensions AND if there is dark matter. Let's suppose that through conservation of momentum, we detect a particle that apparently only reacts through gravity, and there is some...

Homework Statement A piece of machinery of weight W is temporarily supported by cables AB, AC, and ADE. Cable ADE is attached to the ring at A, passes over the pulley at D and back through the ring, and is attached to the support at E. Knowing that the tension in cable AB is 300 N, determine...

I have an equation for a curve that lies along the surface of a truncated cone. In polar coordinates: theta(r) = K * [ U + arctan(1/U) - (Pi/2) ] where: U = SQRT[ ((r/r1)^2) - 1 ] K = SQRT[ 1 + (H/(r2-r1))^2 ] r = r1 + (r2-r1)(z/H) r1 = minor radius of the truncated cone r2 =...

I have a bunch of data x1, x2, x3, ... x49, z. I need a function f(x1, x2,... x49)=z. Does anyone have suggestions for a method that they have used before or key words to google?

Homework Statement Puck A has a mass of 0.0320 kg and is moving along the x-axis with a velocity of +7.65 m/s. It makes a collision with puck B, which has a mass of 0.0640 kg and is initially at rest. The collision is not head-on. After the collision, the two pucks fly apart with the angles 65...

Hidden dimensions of string theory "hiding" in 4D spacetime? Could the hidden dimensions of string theory be "hiding" in 4D spacetime? Thank you for any thoughts.

I'm searching for an online text on units, units systems, dimensions, dimensional analysis and so forth. A nice overview or summary, or an introduction not geared to the complete beginner. Has anybody a good link? thank you

Hello everyone. This is my first post here, though I've stumbled upon the site on several occasions while investigating various physics concepts over the years. I've decided to post now because of a maddening dearth of information regarding the definition of each of the additional dimensions...

in 2d, "curl"(grad(f)) = 0 "curl" is the operation that green's tehorem talks about. In 3D, curl(grad(f)) = 0 and div(curl(F)) = 0. We may consider vector calculus in 4 spatial dimensions, for vector fields F:R^4 -> R^4. what is "curl" like in 4D, since curl is actually only difined in 3D...

Why do they say there can there be no gravity in 2 spatial dimensions (and 1 temporal dimension)? wouldn't the gravitational law be an inverse-law instead of an inverse-square law?

I always here talk of there being multiple universes or there being higher dimensions. When people use these terms are they referring to the same thing? If not, what's the difference?

Homework Statement Evaluate: \int _C{xydx - yzdy + xzdz} C: \vec{r}(t) = t\vec{i} + t^2\vec{j} + t^4\vec{k} o <= t <= 1 Homework Equations The Attempt at a Solution I understand that you cannot use Green's Theorem in 3 dimensions. How else can I go about solving this?

Homework Statement A quarterback claims that he can throw the football a horizontal distance of 171 m. Furthermore, he claims that he can do this by launching the ball at the relatively low angle of 26.2 ° above the horizontal. To evaluate this claim, determine the speed with which this...

Homework Statement A box of mass M=10 kg is at rest on a frictionless level surface (like an ideally smooth ice rink). A rope tied to the box is pulled horizontally, such that the tension in the rope is T = 75 ˆx + 25 ˆz N, where both the x-axis and the z-axis are parallel to the floor. What...

Hi. It asks to calculate the focal length range of a projector of square pixel SXGA is from 4 to 12 m from the screen. It gives the diagonal size of the display (in mm) as well as the horizontal size (in m). The thing that am not sure about is how the focal length would be calculated with the...

I know that string theory tells us that 10 space-time dimensions have a rather special property, namely that a certain central charge vanishes. This allows for an anomaly-free quantization of s.t. Two questions: - are there other statements (not necessarily from s.t.) that something special...

Homework Statement If I have a rectangle rotated at a known angle with respect to a rectangle of known dimensions that inscribes it, how can I find the dimensions of the inscribed/inner rectangle...

I have a question about the dimensions of quantum fields. In natural units, the dimensions of bosonic fields (both scalar and vector) is 1. The dimension of spin=1/2 fermion fields is 3/2. This is all very good, but I have never read any explanation anywhere why we cannot have other types of...