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. K

    What is the spiral shape produced by an attractive (1/r^2)sin(theta) force?

    I was wondering what shape a (1/r^2)sin(theta) force would produce between two bodies. theta = angle between the distance between the two bodies and the velocity vector (90 degrees for a circular orbit).
  2. B

    How Do You Find the Centroid of a Structural Shape with C-Beams?

    I have a problem trying to find the centroid. I have a plate that is 8in wide and .5 in thick. Then 2- C beams (C8x11.5) placed at each end of the 8in beam with the tips facing each other. They do not go beyond the 8 inches. So it's like a U as an example with the tips facing each other. I...
  3. K

    How to calculate Young's Modulus on trapezoidal shape ? Can't find the answer .

    How to calculate Young's Modulus on trapezoidal shape ? Can't find the answer... Hi guys. I'm really stumbling over this question. If I'm trying to calculate the Young's modulus of a specimen that is being compressed from the top, but the contact area on top is smaller than the bottom...
  4. T

    Exploring Shape Resonance in Air: Oxygen and Nitrogen

    Greetings. I've been reading papers on plasma kinetics and have come across the term "shape resonance" a few times when describing peaks in electron impact cross section (function of energy). I have seen calculations attempting to explain these for atoms like helium but I'm not sure how close...
  5. T

    Lift from airfoils, decrease lift as a result of curved shape at large angles?

    Hi, in my point of view lift is created as a result of two pressures, the static and the dynamic. The dynamic pressure is the dominating creator of lift at large angles of attack. For example a flat plane at 45 degrees will create lift. The static pressure is the dominating creator of...
  6. X

    What is the Shape and Size of a Pixel and How Does it Affect Screen Resolution?

    A pixel is said to be an intersection between horizontal and vertical lines on the screen. So does this intersection have a physical shape and size and what happens when an image or video of say 1600X1200 is played on screen having resolution of 800X600 or vice versa. I have searched a...
  7. V

    Helmholtz 2D PDE around general shape (eg a figure 8)

    Hello physics enthusiasts! I was looking for resources, and stumbled upon these awesome forums. I am looking for how to solve the helmholtz equation / wave equation on a figure 8 type shape. I wanted to find the resonant frequencies of a classical guitar. Would this work? I am considering...
  8. L

    Exploring the Shape & Expansion of the Universe

    Hello, I'm working on an assignment where I explain some things about the universe. This is what I'm writing about and also in the order in which I'm writing about it: Part I The Shape of the Universe Matter The static model of the universe A universe which...
  9. D

    Gas pressure and container shape.

    I've been thinking about the ideal gas law lately and there is something I don't understand. Say you have 2 containers filled with an ideal gas. Both containers contain the same moles of gas, the same temperature of gas, and both containers have the same volume. Therefore, according to the ideal...
  10. E

    Shape, structure, and nature of the universe - questions/theories

    Hey guys, newbie here! I stumbled upon your forum while searching for an explanation i was looking for in regards to some theories/questions i have about the shape, structure, and nature of the universe... so here goes! I have some fundamental issues/differences in opinion regarding the...
  11. M

    Is a Deltoid Wing the Same as a Kite Shape?

    As title... I am wondering is deltoid same as 'kite shape'? Thanks in advance...
  12. M

    Shape of titration curve in vol (NaOH) vs vol (HCl)

    In an experiment titration. The NaOH was added drop wise into HCl in a conical flask. The number of drops of NaOH was recorded against the varied volume of HCl in the flask. A graph was to be plotted of number of drops of NaOH on the y-aixs to Volume of HCl on the x-axis. What would the...
  13. R

    Poisson equation: what shape gives largest area average

    When considering the solution u(x,y) of the poisson equation u_xx + u_yy = -1 for (x,y) in G on a 2-dimensional domain G with Dirichlet boundary conditions u = 0 for (x,y) on boundary of G I am wondering the following: for what shape of the domain G do I obtain the largest area-average...
  14. S

    Why Are Planetary Orbits Elliptical?

    Why are the orbits of planets revolving around a body(say the sun) elliptical rather than circular or any other shape? Please show the answer mathematically.
  15. D

    Changing shape of calabi-yau manifolds: flop transitions

    Hi all, I was reading a paper written by Brian Greene sometime ago on flop transitions where one can essentially change the topology of the manifold but the four-dimensional physics that applied to the older manifold still holds. From that I am trying to extrapolate the following: Is it...
  16. C

    Does the poincare conjecture disprove the shape of strings in string theory

    Considering that the smallest particles in nature are supposed to be strings, which are donut and line shapes. And the poincare conjecture says the simplest shape in nature is a sphere. wouldn't it make sense that the true fundamental particles are sphere shaped and that if they combine to form...
  17. D

    Trying to understand the Shape of the universe.

    Please note that I am not trying to forward any type of personal theory. I am only trying to understand generally accepted physics. I have heard the universe described as the surface of a balloon. Inflating the balloon is the expansion of the universe and everything move away from...
  18. R

    Finding Cost of Cylinder with Constant Radius V

    Homework Statement How do I show that when I have C = 4√(3)r^2 + 2π(r)h + k(4π(r) + h), the cost C to make a cylinder of constant radius V gives the following defining equation: (∛(V))/k = (∛(π(h)/r)) x (2π - h/r)/π(h/r) - 4√(3) k is the reciprocal of the length that can be joined for the...
  19. U

    Discrete Model for Buckling Mode Shapes of a Clamped-Free Column

    the buckling shape for clamped-free column is v(x)=1-cos(n*pi/2*L), n=1,3,5 ... how could i use the discrete model to get the buckling mode shape matrix? for example 3x3 matrix form a stiffness matrix and solve the eigenvalue problem? L=1;E=1;I=1 l=L/3 % 3-element beam...
  20. A

    How can we define the universe as having a shape ?

    How can we define the universe as having a "shape"? I'm ignorant, so please excuse me. I've read time and time again over the years on the topic of "the universe" and keep coming across the concept of it having a "shape". Terms like "curved" and "flat" continue to come up and while they...
  21. I

    Predicting molecular shape without drawing lewis structure

    Is their a method for predicting the molecular shape of molecules without drawing the Lewis structure? I am preparing for an ACS exam and would like to try to save some time on these problems. I think I could determine the steric number by counting the total electrons available, and...
  22. H

    Solid Shape Volume by Disk Method Problem

    Homework Statement The base of a certain solid is an equilateral triangle of side a, with one vertex at the origin and an altitude along the x-axis. Each plane perpendicular to the x-axis intersects the solid in a square cross section with one side in the base of the solid. Find the volume...
  23. Tclack

    Figuring Out the Shape of Molecules

    How do you figure out what the shape of molecules are. For example, Water. 1 part oxygen and 2 parts hydrogen with 104.45 degrees between the two hydrogen. That's what I want to figure out. I imagine it has something to do with the electrostatic force.
  24. Tclack

    Determining Shape of Molecules: Water Example

    How do you determine the shape of molecules. water, as an example, the 2 hydrogen atoms are at a 104.45 Degree angle from each other. But how is that calculated? I'm assuming it has something to do with the ratios of the electrostatic forces between the 2 hydrogen and the oxygen.
  25. C

    Shape Operators and Eigenvalues

    This is probably falls within a problem of Mathematica as opposed to a question on here but I have a question about the following: Given some cylinder with the shape operator matrix: {{0,0},{0,-1/r}} We get eigenvalues 0 and -1/r and thus eigenvectors {0, -1/r} and {1/r, 0} by my...
  26. G

    Parameterizing Shapes: Algebraic Form Solutions

    Does anyone have any suggestions on a functional, algebraic form to parameterize the edge of the shapes shown in the image sequence below? It begins as a circle but deforms and flattens along the edges perpendicular to the axis of symmetry. I have a crude model of it with the upper and lower...
  27. J

    Is the Original Figure Considered a Shape in This Puzzle?

    Draw a picture showing four identical shapes where each shape has at least one border with the other three. Your picture should be a single two-dimensional shape containing no gaps or holes. Tried many shape combinations irregular and regular. We got given a hint of not to think or draw...
  28. J

    What is the Shape of the Universe?

    I know how to figure out the shape of the universe. There are three shapes the universe could be. Spherical, flat, or hyperbolic. If it it spherical the universe will someday colapse in on itself. It is not expanding fast enough to overcome gravity. It is slowing down if it is a sphere. If...
  29. F

    Can Four Shapes Share Sides Without Gaps?

    1. Found this question in a past paper i am looking at in preperation for a midterm. Draw a diagram that shows four shapes of equal dimensions with each shape having at least one side in common with the other three shapes. The picture should be 2d containing no gaps or shapes. I do not know...
  30. D

    Ways on how visualize the deflected shape of a simple structure?

    Hi guys, what are some ways to visualize the deflected shape of a simple structure? I know that there is no slope or deflection at fix ends. No deflection at supports (roller, fix ends, etc). Also, I am not really sure what a kink is. Thanks
  31. E

    How are clusters of galaxies formed?

    Maybe I hear somewhere that grups of galaksies forms sphere. Or maybe that groups of gropus of galaksies forms sphere. How it is with this?
  32. T

    Medical Discover the Truth Behind Body Memory: Regaining Fitness After Inactivity

    I often read that if you gain a certain level of fitness ( muscular strength and edurance for example) and then lose it from inactivity, it will be quicker to regain this level of fitness than when you first got it. If this is true then how does this body memory work?
  33. Pythagorean

    Can we use individual spikes as a reliable carrier of information?

    I'm currently reading Spiking Neuron Models by Gerstner and Kistler: But I've also come across this in a review of Spikes: Question(s) Is this really true? Are all action potentials of a given neuron the same? Is that justification for action potential shape not "carrying any...
  34. B

    What shape would the arcade classic Asteroids' universe be?

    I heard this puzzle on the MathFactor podcast (which I highly recommend). If you don't know what Asteroids is (somehow), here's a youtube video: If you fly off the right side, you reappear on the left side, and vice versa. If you fly past through the bottom, you reappear at the top, and...
  35. J

    What Shape is the Distance vs. Time Graph for a Falling Ball?

    Homework Statement What would be the shape of Distance vs Time Graph when a ball is falling? Please explain. Thanks you The Attempt at a Solution I think it will be a curve since the acceleration is constant (9.8 m/s^2) . the slope under the curve will be velocity which will...
  36. W

    Shape of electromagnetic waves?

    Hello. In most texts I have read, EM radiation is depicted as sinusoidal in shape. I understand why this would be the case, as the oscillating fields are often the product of circular generators or alternating current, but is this always the case? For example, is the light we receive from stars...
  37. G

    Calculation the resistance of a spherical shape

    hello there! I was reading about ohm rule in a MIT physics course and they calculate the resistance of a nested spherical shells like this : and they but the microscopic form of ohm's law which is : J=\sigma_q E and I=A J so I=(4 \pi r^2 ) (\sigma_q E) and E=-\frac{\partial...
  38. E

    Determine acceleration of a 2D shape when pushed from any point in its area

    I'm designing a user interface for the web, and it has a physics component. I'm no physicist, but I've got some way towards specifying the problem. Hopefully, someone can help me fully understand it. Here's the scenario. A piece of paper is on the table at a specific location and rotation...
  39. R

    Your physical shape and condition

    Are you satisfied with your current weight and level of fitness? If so, what do you do to maintain it? If not, why do you think you have fallen from it (assuming you were once there)?
  40. W

    What shape would the Univers be if we could see all of it

    I was watching a program some months ago about the Universe and what shape it could be. In the program they used the Atari Asteroids game as an example. As the spaceship starts to go off the right hand side of the screen it starts to appear on the left hand side. As the spaceship starts to go...
  41. B

    Question about the Mass, Volume and Shape of Elementary Particles

    These are some of the inconsistencies with physics that should be resolved on this forum. Question #1. Relationship Between Mass and Gravity) Gravitational fields exist in elementary particles but cannot be detected in laboratory experiments because they are too weak. However can...
  42. A

    Is Forehead Shape related to intelligence?

    Hi, Do different shapes of forehead indicate different degrees of intelligence? Considering humans, Is there any relation between intelligence and forehead shape? Thanks...
  43. R

    Exploring the Spherical Shape of the Nucleus: A Scientific Inquiry

    Why nucleus is spherical in shape in its stable state?
  44. S

    Shape of surface of fluid in a rotating tank

    Homework Statement A concave astronomical telescope mirror may be made by rotating a circular tank of mercury. Find an expression for the shape of the surface in terms of the density of mercury, the radius from the centre, and the rotation rate. Homework Equations v = r \omega The...
  45. T

    Shape of electric lines of force created by an oscillating charge?

    can someone please help me fast? i am having trouble understanding http://www.colorado.edu/physics/2000/waves_particles/wpwaves5.html" ? here it is said that farther away from the vibrating charge the shape of the wave on the line of electric force changes? but is not the shape supposed to be...
  46. F

    Second moment area of symmetrical shape

    Homework Statement -a beam with square cross section, side lengths bXb is rotated 45 degree. -can we assume the second moment area (I) is the same if this is done? Homework Equations I=b^4/12 (cube) I=integral(r^2dr) The Attempt at a Solution
  47. D

    Find the location of the shear center of this shape

    the open cross section shown is thin walled with a constant thickness. find the location of the shear center i have solved this sort of question but never for a circular cross section, at first i thought it should be the same just using polar coordinates instead of Cartesian coordinates...
  48. B

    Shape operator and The Gauss tangent map

    Let M be a surface in R3 oriented by a unit normal vector field U=g1U1+g2U2+g3U3 Then, the Gauss Map G: M to E, of M sends each point p of M to the point (g1(p),g2(p),g3(p)) of the unit sphere E. Show that the shape operator of M is (minus) the tangent map of its Gauss map: If S and G are...
  49. B

    Tangent map, gauss map, and shape operator

    Can anyone help me with this problem?? Let M be a surface in R^3 oriented by a unit normal vector field U=g1U1+g2U2+g3U3 Then the Gauss map G:M\rightarrow\Sigma of M sends each point p of M to the point (g1(p),g2(p),g3(p)) of the unit sphere \Sigma. Show that the shape operator of M is...
  50. F

    What Is the Shape of Acetic Acid?

    what is the shape of acetic acid？
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