What is Shapes: Definition and 164 Discussions

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. kelvin490

    Coating Hollow Shapes w/ Vacuum Evap: Atom vs Ion?

    Is it possible to use vacuum evaporation, sputtering and ion plating processes to coat the inside walls of holes and other hollow shapes of substrates? I wonder whether the source materials are ejected in the form of atoms or ions? Many books say atom but how can they travel to the substrate if...
  2. E

    Can Sound Waves Create Customized Noise Patterns in a Room?

    I learned that with Fourier expansions any function can be approximated by an infinite sum of sine and cosine waves. Is it possible to use this fact to create an arbitrary distribution of sound and silence in a given room. Using a simple example, is it possible to make it so there is noise in...
  3. L

    Volumes of Irregular Shapes by Integration

    Hi all, Is it possible to determine the volume of a shape where, in the x and y dimensions, the shape is described by an equation, and then its elevation is described by another equation? An example would be a parabola in the x-y plane whose elevation is based on another parabolic...
  4. Greg Bernhardt

    Kilobots self assemble into complex shapes

    A Thousand Kilobots Self-Assemble Into Complex Shapes http://spectrum.ieee.org/automaton/robotics/robotics-hardware/a-thousand-kilobots-self-assemble https://www.youtube.com/watch?v=G1t4M2XnIhI
  5. A

    MHB Optimizing Area for two shapes using a single piece of string

    Hey guys, I would really appreciate some help for this question I'm stuck on at the moment: "A piece of 2 m long wire is to be cut into two pieces one of which is to be formed into a circle and the other into an equilateral triangle. How should the wire be cut so that the total area enclosed...
  6. M

    Alternate shapes for compressed cylinders

    Good Morning everyone.. Has there been discussion on here regarding alternate shapes for compressed air cylinders (+3000 psi) I know why compressed cylinder are the shape they are, but in this day and age of science & technology, why are we still using round cylinders? could one not design a...
  7. D

    Bounding General Shapes with Polygons, Especially Concave

    I apologize if this is the wrong forum but I need access to mathematicians who know what's happening with polygonal math. I created an unproven algorithm (or heuristic) back in 1999/2000 for bounding shapes with polygons. It was interesting because it was fast, general for polygons of any...
  8. xwolfhunter

    Representing three-dimensional shapes with functions and integrating

    So, I don't like calculus class, since it's very boring, but I do like math, and I intend to sort of become a mathematical autodidact. So I just thought I'd try to come up with a solution to a problem I created, and this was to integrate one of those gigantor Reese's easter egg things (holy...
  9. M

    Mathematical Number of Shapes: Explained for Intro Physics

    In the following video, the physicist says something about the mathematical number of a shape at 2:49. There's a mathematical number for shapes?? That's beyond interesting. Could someone please give a somewhat simple explanation? I'm only in introductory physics but was told this is more...
  10. A

    Predicting Crystal Shapes: Wulfs Theorem

    Is it possible to predict, at least in theory, which shape a crystal of some combination of atoms would have. If so, what are the principles for such a calculation. I have seen a theorem in classical thermodynamics called wulfs theorem about the equilibrium shape of crystals. Does this explain...
  11. N

    Determine Forces Acting on Rope for Homogeneous L-Shaped Beam

    Homogeneous beam shaped in letter L is suspended on two ropes of the same length l. The beam is of negligible thickness and its longer arm is three times longer than the shorter arm. Its overall length is l as well as the length of one rope. Look at each situation in the figures. How can I...
  12. M

    Rotational Inertias of Different Shapes

    Sorry, this isn't a question from a book or something, but I wasn't sure where else to put this. Is there a convenient way of memorizing or deriving the following?: I have an exam in a week and I thought I might as well try asking before making flashcards.
  13. marellasunny

    The front lateral cross-sectional shapes of cars,what are they fns of?

    BMW has a kidney shaped grill for the air intake but the front looks weird from the side.Looking at a M3 inline-6 from the side,the front seems so long.This brings me to my question,how do engineers arrive at the front lateral cross sectional shapes of cars? I assume that the front lateral...
  14. Q

    Logic Question; Molecular Shapes

    Homework Statement Number 17: http://i.minus.com/jbqSc694thPeBA.jpg Homework Equations I'm not even sure where to start. The Attempt at a Solution I know that tetrahedral shapes are non-polar if all of the attached elements are the same (e.g. CH4 or CCl4). I know all the answer...
  15. 2

    Rotating Shapes: Length of X-Axis at Time t

    As a means of curiosity, I am working on a problem involving the rotation of various shapes. The thing that I am interested in is the cross-sectional length of the shapes as they cross the x axis. So imagine that you have a circle with a pivot point at its bottom. You then rotate it about the...
  16. A

    Archimedes principle and shapes of the body

    Archimedes principle of the force of upthrust = weight of water displaced by the body immersed , but is this law independent of the shape of this body. If we use the idea that the upthrust = P*A on the lower side - P*A on the upper side , if we use it on a rectangle or a square , the only change...
  17. B

    MHB What Are the Areas of Shapes A, B, & C in the Figure?

    in the figure, the area of the interior of the rectangle represents set A, the triangle set B, the circle Set C, indicate the area represented by a. $\displaystyle A\cup B$ b. $\displaystyle A\cap B$ c. $\displaystyle A\cap C$ d. $\displaystyle B\cup C$ e. $\displaystyle \left(A\cup...
  18. A

    Which shape provides the largest area for a given perimeter?

    The problem is posted here: http://nrich.maths.org/5673 I tried subbing in values to get the biggest area: perimeter ratio possible. I used an arbitrary value, 12, for perimeter. For the triangle, I took out the hypotenuse and so A = 1/2(x)(y) where x+ y = 12. Its area is biggest when x = y = 6...
  19. E

    Using radians to discover the lengths of geometric shapes (circles)

    Homework Statement refer to question image Homework Equations refer to question image againThe Attempt at a Solution refer to working out image This is my brothers maths homework. He normally doesn't use online methods to request help and this is his first time.
  20. R

    Conservation of Energy and the Race between Different Shapes on an Inclined Ramp

    Homework Statement Three uniform objects: a ring, a disk, and a sphere all have identical masses and radii. They are released simultaneously from the top of a ramp 3.80 meters in LENGTH. If the ramp is inclined at θ= 17.0°, use conservation of energy to calculate the linear speed of the ring...
  21. P

    Provide some rotations to obtain common shapes?

    I am attempting to use integration to determine the formula for the volume of three dimensional shapes for the sake of practice. My issue is I really lack the skills to determine what type of two-dimensional rotations will obtain a shape. The only one I have been able to do so far has been...
  22. shounakbhatta

    Gravity & Shapes: Ellipse, Parabola, Hyperbola?

    Hello, I might be wrong. Please correct me. In planetary motion or in the size of galaxies: (a) The gravitational attraction of a body, say sun and the force from other planets, creates the elliptical shapes, right? (b) If the gravitational force of anyone body is high than the other...
  23. M

    Guitar Pickups - Shapes of magnets used and their importance

    I'm not electrical minded but I am wondering why my guitar pickup like most have the these rod shaped magnets. Why are they that shape and why is it important? I would like to make my own pickup to understand better how it functions and to see if I can achieve the attempt in making one...
  24. N

    Why Does Mathematics Favor Perfect Shapes to Model Imperfect Nature?

    Why does mathematics deal with the world of perfect spheres, triangles and squares. I understand how this can be applied to architecture and engineering. But this seems counter-intuitive to 'nature' that surrounds us which is objects that are not perfect in shape. The Earth for instance isn't a...
  25. S

    What are the shapes of atomic orbitals

    I know that the shape of s orbital is sphere, p orbital is dumbbell shaped and d orbital is like a doughnut but why do these orbitals have these shapes why not some other shape.
  26. G

    When water freezes, strange shapes may appear

    do you see in that photo how that little stick of ice shoots out from the top? What do you think caused that?
  27. J

    Developing a General Formula for a family of Curve Shapes

    I have a process that requires an operational profile that follows one of the curves in the diagram which follows. I wish to program into the device a general equation that will give me a family of curves of this general shape. The goal is to adjust the parameters of the equation so that I can...
  28. G

    Finding the shapes of all timelike geodesics

    Homework Statement Consider the two-dimensional spacetime with the line element dS2 = -X2dT2+dX2. Find the shapes X(T) of all timelike geodesics in this spacetime. 2. The attempt at a solution I have the solution to this problem but I don't understand one step. For timelike worldlines dS2 =...
  29. M

    Applying principle of superposition to draw resultant shapes. Please help

    Homework Statement Apply the principle of superposition to draw the resultant shape when each of the sets of pulses shown interferes. (Draw the diagrams so that the horizontal midpoints of the pulses coincide.) Homework Equations Please check this website...
  30. D

    Why do capacitor bushings have strange shapes?

    The leads on giant capacitors have always looked mysterious and complicated to me. They almost look like RF cavities to me. Why are the bushings the shape they are?
  31. Y

    A difficult (for me) 3d shapes problem

    If I have a cylinder with a radius r and an axis that passes through point b with the direction of vector n, show that its equation can be written in any of the following forms: 1) ||(p-b) X n|| = r 2) (p - b) X n = r.e (where e s ia unit vector orthogonal to n) 3) ||(p-b) - ((p-b).n)n|| =...
  32. R

    Mode Shapes of a Beam: Exploring Unusual Patterns

    I have never been able to grasp why certain mode shapes are the way they are. For example, I ran a free vibration analysis on a vertical beam fixed at the ground. The second mode shape is vertically straight. This is the same case whether or not I have a lumped mass at the top of the beam. Any...
  33. L

    Create Dynamic Ladder with Java | Learn to Code Java Graphics

    Hi, I have a program that draws four rectangles at a time using a while loop. this is my code. [code = java] import java.awt.BasicStroke; import java.awt.Color; import java.awt.Graphics; import java.awt.Graphics2D; import java.awt.event.ActionEvent; import...
  34. J

    Understanding the Bond Length Differences in sp3d and sp3d2 Hybridization

    Why are the bonds in sp3d hybridisation of different length? And why sp3d2 has bonds of equal length. For me sp3d should also contain all equal ond lengths with a symmetrical shape but it doesnt. Why not?
  35. R

    Natural frequencies and mode shapes

    Hi people, we were doing an experiment in lab where we excite a plate clamped at the circumference at various frequencies to detect natural frequencies. My questions are: 1. Sometimes at certain frequencies, we were observing multiple mode-shapes (an overlap of two mode shapes, to be exact)...
  36. Z

    Algorithm for cutting a polygon into specific shapes

    Hello everybody, I have a shape (polygon) made up from pixels (squares) similar to the image below. I need an algorithm to cut it into "lines" i.e. shapes of 1x[1..20] pixels. The lines should not be necessarily straight, but they should fill the entire area. Any ideas on where to start...
  37. S

    Natural Frequency and mode shapes

    Hi I am using Ansys to find the natural frequency of a structure but this has meant that my understanding of vibrations has become unstuck. When I last studied natural frequencies, it was under free vibration. I formed the impression that one structure can have only one natural frequency...
  38. G

    Mode shapes in experimental modal analysis

    Hi, I am doing experimental modal analysis of a cylindrical casing. I have 64 FRFs. I have curve fitted dominant modes and obtained a synthesised FRF. Now when I see the animation of mode shapes corresponding to each of the frequencies in FRF, I am finding a not-so-significant (amplitude...
  39. S

    How Do You Model a Downward-Opening Cone in Multivariable Calculus?

    Homework Statement Give a formula for a function whose graph is described. Sketch it using a computer or a calculator. A cone of circular cross-section opening downward and with its vertex at the origin.Homework Equations I know how to draw the cone and the properties of a cone, so that's not...
  40. H

    What Is the Method for Conducting 2D Fourier Analysis of Complex Shapes?

    I'm studying for a re-examn in a physical measuring techniques course that includes some Fourier analysis. On old exams there are always a question about a graphical 2d Fourier transform. It can be an ellipse containing a grid of circels, or something like that. In the solutions he takes the...
  41. X

    Arrangement of shapes in an area

    Hello, I'm trying to research a method or algorithm to determine how to best fit a couple of diferent shapes into a given area. Type of area: Rectangular Types of shapes: Rectangles, Triangles, Circles Where I work at we have to figure out how to best arrange the shapes we need into a...
  42. N

    How could strange shapes affect space-time?

    How could "strange shapes" affect space-time? To my understanding anything massive enouph to bend space and time noticeably would end up becoming a sphere due to how gravity works. But what if you could have diffrent shapes that were massive enouph to affect the universe? What if you made a...
  43. J

    Why Do Complex Ions with the Same Number of Ligands Form Different Shapes?

    I'm currently trying to cram knowledge of the transition metals into my head for a chemistry final exam, although i have come across a stumbling block when reading about the 3 dimensional shapes that complex ions form. My textbooks say that complex ion with 4 coordination bonds will form a...
  44. Femme_physics

    What shapes have the greatest/smallest moment of inertia

    I'm basically just trying to find a list of all the shapes and their relative moment of inertia to each other. I want to see what shapes have more and what less, just to get a more intuitive sense to this subject. Does anyone show such a list, or maybe can just tell me of basic geometrical...
  45. K

    Best Fit for 2-D Shapes in Larger Shape?

    Hi, my first post here and I'm not sure I'm in the right place or that I use the proper terms so please bear with me. I'm a programmer by trade, and I'm working on a project whereby I need to arrive at the best fit for a set of 2-D shapes fitting within a larger shape. Mostly we're dealing...
  46. Femme_physics

    Geometrical shapes with an unknown

    Homework Statement http://img857.imageshack.us/img857/3200/thedrawing00.jpg In a rectangle ABCD a square is built, EFGD, and a right triangle BMF, as described in the drawing. Given: DC = 60 cm BC = 40 cm The sum of the area of the square and the triangle is 784 cm2 Calculate...
  47. F

    What do the hexagonal shapes mean in chemistry?

    In chemistry and biochemistry, what do the hexagons with letters in between them mean? Call me silly but for some reason they never taught this to us in school.
  48. P

    MATLAB FEM for natural frequencies and mode shapes of a beam

    Homework Statement Model the above beam with 3 elements(image provided in attachment). Calculate and list the first 6 natural frequencies Plot the mode shapes corresponding to each of the natural frequencies Homework Equations DET(M^{-1}*K + [I] \omega^2)=0 shape functions...
  49. S

    Periodic table of shapes to give a new dimension to maths

    Mathematicians are creating their own version of the periodic table that will provide a vast directory of all the possible shapes in the universe across three, four and five dimensions, linking shapes together in the same way as the periodic table links groups of chemical elements. The...
  50. L

    What are the shapes of orbits that exist in our solar system

    Can anyone help me please? Are they all elliptic or just some? I need to know for planets, comets, moons and satellites All help greatly appreciated.
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