Shape Definition and 638 Threads

A shape or figure is the form of an object or its external boundary, outline, or external surface, as opposed to other properties such as color, texture, or material type.
A plane shape, two-dimensional shape, or 2D shape (plane figure, two-dimensional figure, or 2D figure) is constrained to lie on a plane, in contrast to solid figures.

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  1. H

    Exploring Geometric Shapes of Gravity

    I'm trying to gain a deeper understanding of gravity from a purely geometric point of view (as opposed to the more Newtonian "force" point of view). This thread is the result of a discussion that began in another thread. However, that should not cause a problem for people who are just joining...
  2. I

    Gaussian Curvature, Normal Curvature, and the Shape Operator

    Homework Statement Let u_1, u_2 be orthonormal tangent vectors at a point p of M. What geometric information can be deduced from each of the following conditions on S at p? a) S(u_1) \bullet u_2 = 0 b) S(u_1) + S(u_2) = 0 c) S(u_1) \times S(u_2) = 0 d) S(u_1) \bullet S(u_2) = 0...
  3. L

    Is It Possible To Shape An Electric/Plasma Arc?

    I was watching the visualizer while listening to a song in winamp, and this particular one has two speakers that shoot sine waves. I was watching it and I thought to my self: "it would be great if I reproduce that in real life". After thinking about it my thoughts went to back to that arc...
  4. L

    Mass of chain in shape of parabola

    Homework Statement A chain in the shape of y = x^{2} between x = -1 and x = 1, has density of |x|. Find M, and CM. Homework Equations The Attempt at a Solution \int^{1}_{-1}|x|dx = \int^{0}_{-1}-xdx + \int^{1}_{0}xdx = 1 I got this far and realized that I did nothing with...
  5. R

    How to find out the area of a shape

    Hey this isn't fancy but i thought I'd ask because you are all smart Also i didn't use the template because i didn't really understand it I need help with the area of circles and things because my teachers are not understanding my questions So my question is how do i figure out the area...
  6. jfy4

    Shape of Spacetime: Curvature Tensor or Metric?

    hello, quick question, If i am interested in the shape of space time, am i interested in the curvature tensor, or the metric? Thanks
  7. D

    Name of Circular Standing Wave in Geometry

    Okay, I know this is not that big of deal, but it has been bugging. I would like to know if geometry has given a name to circular standing waves. You know Bohr / De Broglie model. And whether they extend to name with prefixs, like the triangle shaped on being tri-...S
  8. N

    What determines shape of dust nucleus?

    Is a dust nucleus, dust attached to air? If water vapor molecules, attach themselves to dust nucleus in building visible [to the eye] snowflake, I'm supposing flake takes on shape of the dust. Does this mean "air" is shaped too? Don't laugh; I'm most confused!
  9. F

    How to let the cold work shape memory alloy to acquire shape memory properties

    I have a cold work Nitinol wire, my supervisor ask me to do heat treatment at 700 degree celcius after that quench in ice water.He tell me that after heat treatment, the wire will acquire the shape memory properties, but i have repeat for few sample the wire could not function. when i put the...
  10. M

    Reflection of a 2-d shape about some line

    I've noticed the the reflection of a 2-d shape about some line is the same as rotating it by 180 degrees about that line, where it rotates through the third dimension. Does this generalise to higher dimensions? I hope it's clear what I mean here.
  11. B

    Need help solving the differential equation for the shape of a catenary?

    (Moderator's note: thread moved from "Differential Equations") The DE is y''=a*sqrt(1+(y')^2) I have no idea how to go about integrating it, I just started taking diff eq's and haven't taken calc in over a year. Any help would be appreciated, thanks!
  12. B

    How did scientists use WMAP to determine the flatness of the universe?

    Hey guys, I have a question which I've been researching for a while and just can't find much on. The WMAP measures the CMB from the farthest regions of space. It has provided a map of the early universe. Scientists did some work on this and found that the universe is flat to within a 2%...
  13. L

    The shape of infinitesimal objects

    I managed to show that the flux through an infinitesimally small cube equals the divergence of the vector field at that point. I also managed to show that the circulation around an infinitesimally small square equals the component of the curl perpendicular to that square at that point. Should...
  14. P

    Shape of Light: Uncovering the Mystery

    Does light have a definite shape? (this may be stupid question but from many days this question is hanging in my brain Thanks
  15. T

    Vector potential in cavity of arbitrary shape

    we know that vector potential in a resonator satisfies the equation \intA(\lambda)A^{*}(\lambda^{'})dV=4\pic^{2}\delta_{\lambda\lambda^{'} So how about in cavity of arbitrary shape? Does this equation still valid? Thanks!
  16. A

    Shape of a drop on a flat surface

    Homework Statement Dear all, I am trying to find find out the shape of a drop on a flat surface. The requirement is the constant volume of the drop. Any help is greatly appreciated! Homework Equations The Attempt at a Solution I know that for the solution I must find out the...
  17. E

    Can a near-by black hole affect the shape of another black hole.

    Can a "near-by" black hole affect the shape of another black hole. Hello, My name is Edward Solomon and I am curious to know what would happen in the following scenario. Let us assume that we have two Black Holes, A and B. Both Black Holes have the same approximate mass and are not rotating...
  18. marcus

    Supernovae Wind Shape Small Galaxies: Governato et al.

    Governato et al. have offered a solution to a long-standing puzzle about structure formation. Published in the current issue of Nature. http://arxiv.org/abs/0911.2237 Dark matter dynamics (esp. with supercomputer simulations) has already explained a lot about structure formation. For an...
  19. B

    Electric Potential problem, 4 equal charges, different signs, weird shape.

    Homework Statement The drawing shows four point charges. The value of q is 1.96 µC, and the distance d is 0.93 m. Find the total potential at the location P. Assume that the potential of a point charge is zero at infinity. Image of problem is attached. Homework Equations V=kq/r The...
  20. E

    You're in pretty good shape first year physics textbooks

    "you're in pretty good shape" first year physics textbooks.. Hi, I'm wondering if there were any books for which if you were able to do the problems, then you're in good shape.. For example, if you can problems from Spivak's "Calculus" book as you are in your first year, then you're in pretty...
  21. F

    Comparing Light Output of 60W Type A and Type B Incandescent Light Bulbs

    Does a 60W Type A (general service) incandescent light bulb put out more light than a 60W Type B (candelabra torpedo) incandescent light bulb?
  22. D

    What is the Moment of Inertia of a T-Shaped Object?

    h have a T shaped object (2-d) for which i need to find the moment of enertia, i used a parallel axis theorem, then to check myself i found i site which had a direct equation for it http://www.efunda.com/designstandards/beams/SquareTbeam.cfm what i did b1=100mm h1=12mm b2=12mm h2=75mm...
  23. V

    Spatio-temporal shape and spectral distribution of pulse

    Hi, everyone. Can someone help me to understand pulse? What is the meaning of temporal shape? is it means the intensity distribution of the pulse is following the shape? What is the relationship between temporal shape and spectral mode distribution? Is that the Fourier transform...
  24. J

    Derivation of the shape of a clepsydra

    Homework Statement Clepsydra was a water clock used in old times in which water was allowed to espace through a small hole at the bottom. Find the shape of the clepsydra, if the water level is to fall at a constant rate. Homework Equations Torricelli Law The Attempt at a Solution...
  25. A

    Representing a point in an n-dimensional space in a 2D geometrical shape

    Is it possible for me to use a Voronoi diagram - or some other algorithm - to represent a point in an multidimensional space (between 5 and 10 dimensions) in a 2D geometrical shape? (And more interestingly, in a geometrical shape that is a) fairly small, and b) looks aesthetic. I have a...
  26. T

    Strange hexagonal shape on Saturn's north pole.

    http://www.examiner.com/x-5182-Dallas-Weather-Examiner~y2009m12d10-Solar-systems-greatest-mystery-at-Saturns-north-pole If anyone here knows a lot about astronomy, and astro-physics, could you please try to scientifically explain this? The same shape appeared on Jupiter about a year ago...
  27. L

    Modelling the shape of an atom

    hi, when modelling the shape of a hydrogen atom orbital, is it the real part of the spherical harmonics that i plot? thanks
  28. O

    Volume of a shape with a different trapezium at each end

    1. Volume of a shape with a different trapezium at each end. Trapezium 1: a(top side) = 65.5m, b = 35.5m, h = 3.5m, height above sea level = 3m. Trapezium 2: a = 53m, b = 17.5m, h = 3m, HASL = 1.6m. Trapezoids are parallel and 48m apart. Their horizontal centres are aligned (as in sections of...
  29. L

    Looking for visual models or discriptions of bullet vs. shape charge

    Hello, I'm creating a slide-show presentation that describes how a shape charge explosion (namely that of an improvised explosive formed projectile) is more effective than that of a bullet projectile. I would like to include visuals and equations which describe how the initial explosion...
  30. V

    Calculating or Modeling Resistance of a Complex 3-D Shape

    Hello all! I am looking for a method to calculate or model a resistance of a complex 3-D shape. For example if I have the resistivity of a material, and I know the shape (let's say a cone), I would like to be able to model the resistance which this shape will produce. I am looking for...
  31. M

    The shape of an object affects it's free-fall density

    Homework Statement Identify evidence that the shape of an object affects it's free-fall acceleration Examples would help. Homework Equations N/A The Attempt at a Solution Wind resistance would be different for an egg as compared to a rubix cube
  32. PrincePhoenix

    The shape of our solar system's orbits.

    What's the shape of the planets orbiting the sun in our solar system according to this website http://www.chacha.com/question/what-is-the-shape-of-orbit-of-planets they are elliptical. But in a documentary (maybe history channel's "The Universe", but I'm not sure) I heard that our solar system...
  33. P

    Calculating y-Coord of Center of Mass in Unique Shape

    Homework Statement ____ l _ l l_l l_l Find the y-coordinate of the center of mass. Each side l / _ is length a. I got an answer of 1.25a, but that isn't right. Homework Equations The Attempt at a Solution Area of each section * x-coordinate of center of mass. (the area...
  34. T

    Exploring the Spherical Shape of Nuclei and Resources for Further Research

    Is the notion of spherical shape of nuclei well proven by experiment? Could someone please direct me to a relevant source?
  35. V

    Acceleration of the Photon and the shape of it's wave

    Hello Again Regarding photons: Is there any small transient time lag or "ramp up" between their point of emission and their full speed. In other words do they go Zero to 186,000 miles per second in all of an instant? And have there been any experiments to see if this is an instantaneous full...
  36. P

    Why rainbow has a shape of arc and why its ends are bent down.

    why rainbow has a shape of arc and why its "ends" are bent down. Can anyone explain why rainbow has a shape of arc and why its "ends" are bent down.
  37. B

    ODE modeling a curved reflective surface, describe shape of curve

    Homework Statement Assume that when the curve C shown below is revolved about the x-axis, it generates a surface of revolution with the property that all light rays L parallel to the x-axis striking the surface are reflected to a single point O (the origin). Use the fact that the angle of...
  38. B

    Sketch Output Voltage Shape at 300rpm | 30V Amplitude

    Homework Statement In a particular application, the generator output is converted to DC and used to power an immersion element for water heating. 1). Sketch the shape of the output voltage at a rotation speed of 300 rpm assuming the amplitude on each phase is 30V? The Attempt at a...
  39. R

    The shape of space-time and physical constants

    I am wondering if anyone knows of research being done, or theories that are related to the actual structure of space-time as they are related to physical constants such as the speed of light, Planck's constant, and the cosmological constant. I'm far from being a expert, but I've been playing...
  40. I

    How to quantify the shape of a sequence of data values

    Hello, So I was wondering how I would measure and or quantify the shape of a sequence of data values with two values (an entry and an exit angles to/from the max) Say we have a set of values like: 0,5,10,5,0 If we assume the x-axis incremental is by 1 and plot this on graph paper we...
  41. mg0stisha

    Mathematica Feedback on Mathematica 7 and "Six Ideas That Shape Physics"

    Hello, I was just wondering if anyone has used the software Mathematica 7. I heard it's a really good program and with the new functions it looks great, i was just wanted to get some good user feedback from people who definitely know what they're talking about. Thanks! P.S. - as a side note...
  42. Loren Booda

    What shape building is most energy efficient?

    For a given spatial volume and amount of material, what practical structural design conserves temperature best?
  43. D

    Not sure about shape of this quantum well

    Hiya guys, i have a quantum well in strange notation I have never seen before. I think i can do the question, i just need to know the shape of the well. If someone would be so kind to draw me a shape (I think its a step but not sure?). It is: dphi dphi...
  44. S

    What Are the Exact Scherrer Shape Factors for Different Crystallite Structures?

    The Scherrer equation is used to determine crystallite sizes from XRD spectra. they contain K, a shape factor, that varies from 0.89 for spherical to 0.94 for cubic particles. Usually, this is set to 0.9 for particles of unknown size. Does anyone know where we could find a table with the exact...
  45. jaketodd

    What Is the Shape of a Free Electron Wave?

    What is the shape of a free electron wave? Is it a sinusoidal plane wave like an EM wave? Does it expand laterally like an EM wave? I'm thinking the answers to these questions is yes because the double slit experiment works for electrons. But I'm not totally sure. Thanks! Jake
  46. I

    Transformation of one shape into another

    I have been out of class for really long, I don't remember anything, I have lately become interested in transformation of one shape into another. :confused: Is this also about topology ? If so, I would like to know how you can define such a beautiful transformation ? It is just so strange to...
  47. V

    Shape of Nuclear Explosions: Exploring Archimedes' Principle

    why do they form the shape they do? that is after a nuclear explosion i'm familiar with thermodynamics and fluids ect..., does it have something to do with archimedes principal?
  48. G

    Does a black hole have shape?

    Does a black hole have "shape?" Today I was watching the Science Channel and a program on the Hubble telescope was on. It was said that pictures of black holes have been taken not by the Hubble, but by another similar device that takes pictures of Gamma and/or X rays. This...
  49. D

    Changing The Shape of a potential well

    This question was posed to me a while ago, but I never fully understood how to solve it. You have a particle in the first excited state of the infinite square well (with the origin taken to be at the center. You "abruptly" change the shape of the potential well to be that of the harmonic...
  50. M

    Tesseract: 4D Shape Constructed? Fact or Fiction?

    iam sorry if this is crackpottery,but is it true that a 4 dimensional figure*called the tesseract has been constructed,i came across this over the net.*kindly rebuke me if iam not abiding with the rules of pf.
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