Beams Definition and 259 Threads

  1. M

    Mechanics of materials ques / stresses in beams

    Homework Statement refer to attachment Homework Equations The Attempt at a Solution I am completely confused at where to start can someone get me going in the right direction here as to one of the answers.
  2. S

    How Much Bending Moment Can a Plyweb Beam With Timber Flanges Carry?

    Calculate the maximum B.M the symmetrical section can carry Plyweb with timber flanges (50x100 c.s.a) The maximum stress = 1.0N/mm^2 The structure is essentially an I beam with dimensions as follows. The central beam has a width of 25 and height of 500. The four flanges which...
  3. A

    Particle beams in space rockets

    I'm currently working on a new paper on how to increase the efficiency of space rockets (both in performance speed and power). Getting the idea from a simple CRT (Cathode ray tube) and how the beams make an object move in the tube; I came up with this idea to use the same thing in a typical...
  4. E

    Calculating Reaction Forces and Maximum Bending Stress in Simply Supported Beams

    simply supported beams? [b]1. Can anybody help me? please. This seems like I have gone completely off track. A simply supported beam of length 6m supports a vertical point load of 45kN a distance of 4m from one end. If the maximum allowable bending stress is 120MPa: (there were 4 previous...
  5. L

    Question involving load on beams

    Hey, so there are three loads on a beam the units they are is in pounds (i.e. 7200pounds is one of the loads). There are two cases each for which I need to calculate reactions and draw bending moments and a sheer force diagram. The PDF attachment contains the information in more detail help...
  6. J

    How far from the entrance will the beams of the different isotope ions end up?

    Homework Statement There are three main isotopes of carbon, with the following atomic masses: Atomic Masses 12^C 1.99 x 10^-26 kg 13^C 2.16 x 10^-26 kg 14^C 2.33 x 10^-26 kg The atoms of carbon are singly ionized and enter a mass spectrometer with magnetic field strength B = 0.200 T at...
  7. ZapperZ

    Accelerator and Beams - Tools for Discovery and Innovation

    The Division of Physics of Beams of the American Physical Society (APS) has produced this wonderful brochure titled "http://www.aps.org/units/dpb/upload/brochure.pdf" ". It essentially describe what a particle accelerator is, and more importantly, what it is used for. The main purpose here is...
  8. J

    Question:Parallel capacitors and electric beams

    An electron beam is send perpendicular onto an electric field between two capacitor plates. The electrons got their kinetic engergi by being accelerated through a potential difference V. The potential difference between the capacitor plates are also V. The distance between the plates is d, and...
  9. J

    How do I calculate radial stress in a u-shaped t-beam with varying thickness?

    I have a u-shaped t-beam, and I am trying to calculate the radial stress where \theta=0 degrees. I have calculated \sigma\theta_{} but I am unclear on how to treat the varying thickness of the cross-section when integrating with respect to radius.
  10. A

    What is the Deflection of a Simply-Supported Beam?

    Homework Statement Deflection of simply-supported beam problem. Please see the attached image of an example problem from a textbook: http://img14.imageshack.us/img14/619/hearnbeamproblem.png I have absolutely no idea why A = - (wL^3)/24 and why 0 = (wL^4)/12 - (wL^4)/24 +AL is used in...
  11. C

    How Is the Deflection Formula for a Simply Supported Beam Derived?

    Hi,:smile: I am only new to this forum so any feedback would be greatly appreciated. I am wondering if anyone could help me derive the formula for a simply supported beam with a uniformly distributed load. I understand that it is done using integration but I fail to understand the steps...
  12. A

    Composite beams and young's modulus

    Homework Statement "A polymer, with Young’s modulus 2GPa and yield stress 50MPa, is reinforced by uniaxially aligned glass fibres which have Young’s modulus 70GPa and fracture at 1400MPa. The volume fraction of fibres is 40%. (a) Calculate Young’s modulus for the composite in the...
  13. R

    Young's double slit experiment beams

    Homework Statement In a Young's double slit experiment, a pair of slits is encased in a rectangular block of glass (n=1.52), and glass block is surrounded by air, as shown below. The glass block is illuminated by coherent light (k = 660 nm) from a laser, as shown. The beam enters the block at...
  14. P

    Help with Solid Mechanics Assignment: Stress, Deflection, Beams, Macaulay's

    i have an assignment due this thursday, it has 9 questions, i was able to solve five of them. but for some reason i missed most of the classes in second term so i don't understand anything about the last four questions. the questions are: Question 1: A beam is simply supported and loaded...
  15. B

    Bending of Beams - Deflection - Stress - Strain

    Homework Statement A beam of lengh is supported in a clamp system. distance between clamp is 1m. Loads applied at 250mm and 750mm. strain gauge fitted at 175mm with 100ohm resistance. Weight is applied at points a and b. Homework Equations Dont know? The Attempt at a Solution I...
  16. S

    Is there a weapon that beams particles like a taser?

    My friend insists she is being "hit" with something that causes her pain. She has no diseases that would cause the pain. At first I thought she imagining things but after further investigation, there are reasons to believe her. She said she saw three different persons have a baton or wand which...
  17. P

    Two coherent beams crossing each other's path; what will be the effect?

    A laser beam is split into two beams. After traveling some distance they cross each other's path. I was just wondering this crossing will have any effect on the beam properties or not. More basically, if two coherent beams one heading north and the other heading east cross each other at origin...
  18. T

    How Far Can Chris Walk on a Cantilevered Beam Without Tipping?

    Homework Statement Chris and Robin use a 3m, 40kg, plank to span 2m over a river. The plank is set up with 1.0m on the bank and Robin is standing so that her centre of mass is 0.2m from the end. The diagram attached shows Chris (50kg) walking out on the plank. Robin has a mass of 80kg...
  19. J

    Possible to make 2 beams of light cancel?

    Last night, I was doing some really cool stuff with light interference, like the double split experiment and such. so, then i started wondering, is it possible to make 2 beams of light from different sources cancel each other out? [see attachment (gray are represents steam or something to make...
  20. L

    Calculating Deflection and Shear Flow in Riveted Beams

    Homework Statement A beam loaded by a central point load deflects a quantity, e.g. d. If an identical beam is laid on top of the first beam and the same loading is applied the deflection drops to d/2. In this loading situation the ends of the beam are not aligned. When the beams are joined...
  21. P

    So structural beams are used pretty much everywhere right?

    like everyday homes and highway bridges and almost every other building right? just making sure... I mean, I've never actually seen an everyday home being built and you can't see them just by standing inside the house.
  22. W

    High-Energy Beams: Finding W & Z Bosons

    I read on http://cern-discoveries.web.cern.ch/cern-discoveries/Courier/HeavyLight/Heavylight.html that to find the W and Z bosons they used beams with 270 GeV of energy per beam. But the W and Z bosons have a mass of about 80/90 GeV, how come so high-energy beams was needed?
  23. J

    Arches or Beams: Why Arches Hold More Weight on Pasta Bridges

    Why do pasta bridges made with arches or triangular peaks hold more weight than those made with a flat beam? Assume the weight is attached to the base or deck of the bridge.
  24. R

    Why Are 1.2m and 0.45m Unnecessary for Determining Force F?

    In the attached diagram, if the beam was not undergoing any rotation would this be because the couple C1's forces are being canceled by the x components of the forces F and -F and also because the y components of the forces F and -F are canceling each other out? So if C1 was known and the F...
  25. J

    Two oposite beams and earth and rocket again

    I am sure this question in some form gets posted here all the time again and again, but I somehow can not find it in the form I would recognize, so my appologies for probably posting it again. So one of the classics: Two light beams - A and B get launched from Earth to the opposite directions...
  26. P

    Help for project looking into the amount of load's beams can take

    Hi guys I was wondering if you could help me out with designing a project. I am looking into how much load different beams can take. How should I weigh down the beam? Should I put load on top of it or hang it from the bottom, or something else? If on top, should I just load it all directly on...
  27. E

    How Does the Reciprocal Theorem Apply to Beam Deflection?

    I am trying to learn and figure our the reciprical theorem when applied to beans and the deflection on a beam when a load is applied. The beam would be x long, say 10m and would have a weight/load applied at 5m, or dead center. There would be point A (Dead Center) point B (Half way between...
  28. F

    Calculating Torque T & Q for I-Beams & Torsion

    You have two parallel I-beams. A trolley with 4 wheels runs on top, and carries a total load of say 10kN. How would you evaluate the torsion? angle theta = TL/GK where (for an I beam) K = [2bt^3 + (d - 2t)(thickness of web)^3] / 3 and t = thickness of flange But, how would you calculate...
  29. P

    What happens when two light beams collide ?

    Iam very new to this forum. I just had this doubt for the last week. pardon me if this is a silly one. the doubt is : what happens when two light beams traveling in perpendicular directions collide ? collide in the sense i mean what happens at their intersection point ? what i have...
  30. Q

    Hollow sphere or sphere with beams

    A friend and I debated what is the 'stronger' structure: a hollow (fluid filled) metal sphere or a metal sphere with one or more metal cross beams that span the sphere diagonally given that the same quantity of material is used in both. By 'stronger' I mean the resistance to compressional forces...
  31. W

    Calculate Min Drum Diameter for Copper Strip 4mm Thick, max Stress 332MN/m2

    Homework Statement 3. Calculate the minimum diameter of drum on which copper strip 4mm thick may be wound if the maximum bending stress is not to exceed 332MN/m2. Assume E = 95 GN/m2 σ /(yxE)=r Homework Equations The Attempt at a Solution would this work if so i make it...
  32. F

    Statics- beams internal effects i dont get it

    Homework Statement this is a picture of an example from the book. I am going off of it to solve a problem that will be on my test tomorrow. i can figure out how to calculate the shear force and moment of each section (though i don't fully understand it), but I am just not getting how they...
  33. M

    Shear Forces and Bending Moments in Beams

    Homework Statement (Q) A beam 4m long is supported at the left hand side by a hinge support and on the right by a roller support. It is under a non-uniform load intensity throughout by a load intensity given by: w = 25Cos(pi x/8)kN/m. Write equations for the shear force and the bending...
  34. S

    Temporal overlap of light beams

    Let's assume I can generate two individual light beams, one centered at a wavelength of 800nm (visible) and the other at 3450 nm (infrared). Obviously the visible light has a higher frequency than the infrared light. Since all EM waves travel at the speed of light, how can one achieve...
  35. R

    Castigliano's Theorem on Curved Beams

    Homework Statement You have a semi-circular cantilever with a point radial load at its free end. i.e load acting down from top of semi circle, with bottom attached to something. Calculate the equations for the horizontal and vertical deflections taking into account both bending moments...
  36. B

    Where Did I Go Wrong in Solving This Physics Problem?

    Appreciate if someone could take the time to look at the following problem, my answers, and can point out where I have went wrong. Also, part 4, I think more info. is needed to determine this, but I may be wrong. Anyway, here goes: A hoist motor is attached to a support beam as shown in the...
  37. R

    Structural analysis influence lines in beams

    Homework Statement http://antishift.org/image.php?id=16122&size=medium Homework Equations Static Equilibrium equations: since most of the supports are rollers, only y-forces are considered as well as moment equations. I'm pretty sure E and F are hinges so there are no moments around E and F.The...
  38. R

    A (hopefully) easy question to answer about cantilever beams

    Hi guys, just wondering if you could help me out? For a standard rectangular cross-section cantilever beam with a concentrated end load how do i work out the top surface stress at a point along the beam? do i just use sigma=My/I where y=half the depth of the beam and M=end load * distance...
  39. J

    Solve Cantilever Beam: End Load 20kN, EI=40KNm^2, Length 0.25m

    Homework Statement A cantilever beam carriers an end load of 20kN and has an EI value of 40 KNm^2. If the beam is 0.25m long, use intergration to determine the slope at the free end of the beam? Homework Equations I know from a handout I have that the fudamental equation to...
  40. N

    The Unruh effect and light beams

    According to the Unruh effect, an accelerating observer will find himself surrounded by a "warm bath" of particles (see http://en.wikipedia.org/wiki/Unruh_effect ). Now consider two observers,A and B, one accelerating (B) and the other (A) in constant motion (or rest). Let the accelerated...
  41. B

    Calculate Deflection of Beam Under Point Load

    How do I calculate a deflection under a point load?
  42. J

    How Do You Calculate the Energy of an Electron Beam in an Electron Gun?

    Hey guys Apparently I have to know how to find the energy of accelerated electron beams for a test, and I'm not sure how. Any help? I'm assuming it's talking about electron guns: I think this consists of a heated cathode which emits electrons via thermionic emission, and an anode which...
  43. J

    Discovering the Energy of Accelerated Electron Beams by Jonty

    Hey guys Apparently I have to know how to find the energy of accelerated electron beams for a test, and I'm not sure how. Any help? I'm assuming it's talking about electron guns: I think this consists of a heated cathode which emits electrons via thermionic emission, and an anode which...
  44. A

    Intensity and Interference of Light Beams

    i have to do a physics assignment and i got stuck at this quesion hope u guys can help. An interference pattern is formed on a screen by the superposition of two coherent light beams, one of which has four times the intensity of the other. What is ratio of maximum to minimum intensity in the...
  45. Ivan Seeking

    What Mystery Shrouded the 1979 UFO Encounter with Deputy Val Johnson?

    http://www.grandforks.com/mld/grandforks/news/14757502.htm
  46. J

    What Spray Could Make Laser Beams Visible?

    Hello, I was wondering if anyone has ever seen a movie where some people are robbing a bank or art gallery, and they spray something to make the laser beams show. Does anyone know what type of spray could do this? I have tried google, and I didn't know if this is the right place to ask...
  47. Astronuc

    What Are the Different Types of Beam Cross-Sections?

    Beam cross-sections http://www.efunda.com/math/areas/Common_Cross_Section_Index.cfm Standard beams http://www.efunda.com/math/areas/IbeamIndex.cfm About 10 or so free look ups. Requires subscription Monthly (recurring till cancelled) $6/month Student $36/year Professional...
  48. P

    Complete EM Field of Gaussian Beam: References & Pointers

    Does anyone have any references or pointers to the complete electromagnetic field of a "Gaussian Beam"? By Gaussian, I mean that for a beam propagating in the z direction, a cross-section of the beam in the x-yplane has |E| = k exp( -(x^2+y^2)/w^2 ) see for instance...
  49. C

    How Can You Accurately Measure Strain in Steel Beams with Low Load Cells?

    How does one work just out of interest? I use it when loading a steel beam to see the strain induced in the web of a chanel section. can't figure out how it would work
  50. J

    Why Is the I-Beam Shape Optimal for Moments of Inertia?

    I recall that the shape of an i-beam is near optimal because of its moment of inertia. Does any have a reference that shows this, with explanation?
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