Beam Definition and 1000 Threads

Homework Statement The answer is to be given in terms of L and w. The picture shows a beam of weight w and various blocks on it also each of weight w. It also shows the gravitational force acting downward on the center of gravity of the beam. The beam rests on a triangular pivot point. 2...

For a Gaussian beam, which has 86% of its power within its beam diameter (spot size 2w0), I've read that beam (angular) divergence is given by 2θ = 4λ/(π[2w0]) Where does this come from? I hate memorizing equations. It makes me feel stupid.

Hi All As shown in the attached image, I have a simply supported beam with a load of 150kN acting at the center of the beam span. E = 210 GPa rho = 7800 kgm-3 span = 250 mm After solving this in FE solver, I got maximum displacement to be ~4mm (at node 52) But, on using the theoretical...

: Homework9-7 http://physci.kennesaw.edu/images/hm12-1.gif 1. A uniform beam of mass m is supported in a horizontal position by a pin and cable as shown in the Figure. Given. m = 20.0 kg ; M1 = 54.0 kg ; M2 = 37.0 kg ; L1 = 2.90 m ; L2 = 5.40 m ; and θ = 43.0°. a) How many forces are acting on...

Homework Statement [Ans: FA = -206i + 188j lb, T = 131 lb] Homework Equations Since it's assumed that the system is in equilibrium, so I assume that ΣF=0 and ΣM=0 The Attempt at a Solution I tried to draw a free-body diagram for the system, and set up three equations below: (I don't know...

Homework Statement If the electric motor of problem 3.66 is to be mounted at the free end of a steel cantilever beam of length ##5## m and the amplitude of vibration is to be limited to ##0.5## cm, find the necessary cross-sectional dimension of the beam. Include the weight of the beam in the...

Homework Statement I have a steel cantilever beam of length 5m, width 0.5m, and thickness 0.1m. The beam has uniform density. Homework Equations \begin{align*} M &= \iint_D\rho(x, y)dxdy\\ \rho &= M/\ell \end{align*} The Attempt at a Solution If I don't know the mass or density, how can I...

When you collimate a point source using an off-axis parabolic mirror (OAP) with a circular shape, the beam area of the collimated light becomes more and more elliptical (x-dir. is smaller than y-dir.) as the off-axis angle is increased. Is there a reason why this happens? And is there a way to...

I would like to calculate the maximum stress in a hollow beam being bent laterally. There has been some discussion in my office about the correct way to view the system in question, and so would like some other opinions on the matter. I will include pictures below. In simplified terms, the...

Hello I am creating a torsional testing rig for a Formula Sae car, the front of the car will be pivoted about the center on a beam with the loading off to one side. In the design I need to calculate the deflection of the beam in order to determine which material and what profile of metal will...

Consider the above experimental setup. Here the source can emit one photon at a time. The output from the source is sent to a beam splitter which divides it into three possible paths of equal probability. Splitter 2 further splits the path 3 into two paths of equal probability. We have...

Hi, I have an experiment set up to get two beam interference fringes. I would like to know how I could measure the actual amplitude of the irradiance from the experiment. I have with me a power meter and a CMOS camera. How can I go about this? Thank you

Homework Statement Okay this is the problem I have: I have a Steel Channel beam which has an cross sectional height of 300mm. It is 150mm in depth. Its wall thickness is 20mm. This beam is 6meters long as has a 10kN/m UDL applied. It is fixed at one side and unsupported at the tip. I have...

https://www.physicsforums.com/attachments/73840 This is the problem I don´t understand, I know I hace to determine the distance z1 which correspond to the widht W1, but I try to solve equation of W1 and W2 for z1 and use the fact z2 = z1 + 0.1m, but I, my question is how to determine the waist...

Our test group had some issues with an ASTM foam cushion drop test, and I was asked to investigate. I fixed the problem, but noticed something in a high speed video. A 50 kg mass on the hinged platform separates from the platform when the raised end of the platform is dropped. I thought the...

Alright so I drew it out like did the reactions and everything then I realized I need to include the diameter of the beam. How do I find the max bending stress while using the diameter of the beam? All I need to know is what exactly I do differently compared to drawing the bending moment...

Hi!. I´m modeling a gaussiam beam. I found that considering the electric field distribution of Gaussian laser pulses along the axis of propagation, we can write the intensity as: Where y = I_l R is the power is the power reflection coefficient y = w_0 is the beam waist radius at y = z=0...

I need help with this beam deflection problem for 1 the book my professor gave me almost everything is hand written including the beam stuff... SO I can't read it at all and its really frustrating trynna do this without being able to read the formulas or anything please helpp! I attached the...

Homework Statement A beam of thermal neutrons emerges from a nuclear reactor and is incident on a crystal as shown in the figure below. The beam is Bragg scattered, as in the figure, from a crystal whose scattering planes are separated by 0.253 nm. From the continuous energy spectrum of the...

i am working on the beam theory. where i have to consider a pure bending of a beam. they question asked was i should motivate the formula for strain \epsilon and use a setch to explain. how do i motivate the formula

The problem is to apply Schrodinger wave equation to a beam of mono energetic electrons and show that the probability of finding electron at each point on the beam is constant (d2ψ/dx2) + (8∏^2m/h^2)(E-V)ψ = 0 I have been taught to apply this to a single particle for various...

A 1-ton wall hoist consists of a horizontal beam, supported by a tension rod at 30 deg, as shown. The rod is to be designed with a factor of safety 5 with repeat to its yield point of 30,000 PSI. Determine its necessary cross section S=F/A 30000/5=6000PSI -2000+Rsin(30)=0...

Hello all, I need to calculate the bending stress of a tapered cantilever beam. However, I would like to know how to calculate the moment of inertia. For a uniform shape beam, I know the Ix=(bh3)/12, but since h changes throughout the length of the beam how would inertia, I, be...

I guess we all know laser beams. I wonder if we can make beams in the microwave frequency range and how the beam width relates to the frequency, e.g what is the minimum beam width we can achieve with a frequeny of 50Ghz.

I have already balanced beam both side two same mass at same distance and it is pivot on its center of gravity...so torque is zero so no rotation possible by gravity on earth......so why beam always be horizontal to Earth surface...after give inclination to Earth surface.....potential energy not...

hi please if anyone can tell me how i can get the following equation (attachments) of deflection for statically indeterminate cantilever beam with point load (attachments). I'm not an engineering student and having difficulty in coming up with boundary conditions. looking for help. thanks

I've recently started doing a lot more residential structural engineering for local clients and the first thing that I realized was that I was lacking a good beam calculator. I do have a number of spreadsheet calculators but I've found them hard to program and once I do have them programmed...

Hi everyone. I feel there should be a simple answer to this but I can't seem to find anything on this. So I have a simple cantilever beam, supported at one side and loaded at the free end. I have the force displacement data and can easily calculate the stress. However, for the strain I do...

i have a 20.5ft c3x5 steel channel with a point load at the exact center and i wanted to determine its maximum deflection. the point load is 921.86lbs, and moment of inertia is 1.86in^4. modulus of E= 30,000,000psi

Beam held up by two columns I apologize in advance if you think this should really go in the homework help area, I am not sure because this isn't a homework problem, but rather my struggle to understand and carry out concepts. If it needs to be re-posted, or moved, I understand. :) In a...

Consider the following experimental setup: the front half of a klystron tube (the electron gun and resonent cavity) or perhaps a free electron laser, several different targets consisting of a highly conductive(metal) object, a possibly conductive object(salt or clay), and a non-conductive...

My understanding is that a light beam will bend in an upward accelerating elevator. I told my uncle this. He responded that the velocity of the elevator cannot be added to the velocity of light since light's velocity always remains the same no matter the motion of the source or the observer...

I am a lighting designer for tv shows and I have a problem with a location that has very low ceilings and 22" timber beams running the width of a 30ft room. The location is a listed/heritage building and therefore we cannot cause any physical damage to the property including the ceiling. I...

Hello everyone, I am wondering how to properly go about calculating the stresses caused by bending on an angled flat plate. Two approaches seem valid but they give much different results: -Calculate the new area moments of inertia for the angled flat plate (new Ixx, ymax)...

Definition/Summary A Gaussian beam is an electromagnetic wave, usually a laser beam, with a Gaussian cross-sectional irradiance pattern. The Gaussian irradiance profile results in minimal spreading due to diffraction effects. The spot size w represents the radius or half-width at which the...

This is a problem from Michael Lindeburg's FE Review Manual. It is in Chapter 20, Number 11 if you have the book. PROBLEM: There is a picture of a cantilever 2 m in length attached to a wall. There is a force applied at a 30 degree angle from the horizontal at the free end of the beam...

Homework Statement An intergalactic cruiser is approaching a hostile spacecraft . Both vehicles move at a constant velocity. The velocity of the cruiser relative to the spacecraft is vCS=+0.7c, the direction to the right being the positive direction. The cruiser fires a beam of laser light...

I am somewhat confused about the connection between divergence and solid angle for a beam. I know individually what each term means... but I'm confused as to how (or even if) one can calculate the solid angle of a beam, given the divergence. I have some notes from a previous lecture series I...

hi every body I want to analysis a beam with one degree freedom on apdl (ansys software) This software give me a different period! for beam with mass=stiffness=1 we must have 2π value for period but this program give me another answer.

Hi there, I'm looking for some information on the current limits of the beam width of currently available lasers. I'm less interested in experimental setups that are not on the market yet, but I suppose if one of them is markedly different it would be interesting to know. Specifically...

A light in a lighthouse $1$ km offshore from a straight shoreline is rotating at $2$ revolutions per minute. How fast is the beam moving along the shoreline when it passes the point $\frac{1}{2}$ km from the point opposite the lighthouse? ok we have a right triangle where the $\theta$ is the...

I am performing an experiment for my project. I have bended an aluminum beam of 1in by 1/4 in by 14 in (Al 6061 T6). I deflected the beam upto 0.09 in at the middle. I need to find Sigma x, sigma Y and Shear stress on the expanded and compressed face of the beam which is 1 in by 1/4 in. Can...

Homework Statement Find the shear and bending moment diagram for a fully restrained beam with a length of 5m, a uniform distributed load of 1kN/m from x=0 to 2m, a point load of 1kN at 2m, and another uniform distributed load of .9kN/m from x=2, to x=5. Homework Equations The...

Hello again, My handy optics engineer has left the country leaving me with a problem that's over my head. I need a low cost (i.e. $500.00) solution to produce a circular, collimated, 405nm beam. My beam needs to be within the target diameter (+/-20%) from 0 - 4" from the output lens and...

I read that there are polarizing and non polarizing beam splitters. Are there adjustable bleam splitters between them?

Hey Guys, I'm stuck with this problem, we want to compare the curve of a beam to it's horziontal deflection, it's for an experiment we're performing on a very elastic beam. In the attachment you see a flexibel beam getting deflected by a force, this causes displacement x. We don't know (or...

i wonder about tesla death ray. is this machine really exist ? or just conspiracy theory ?

I am trying to simulate a Gaussian beam through an optical waveguide having a circular cross-section in matlab. I am familiar with the theory of modes in an optical fiber and can analytically calculate the evolution of the beam by breaking down the beam into a sum of infinite modes. However, I...

I have two independent variables (rotation in degrees, and distance from best focus distance in mm) and one dependent variable (1/e^2 width squared in mm^2). How would I go about creating either a multivariable function or a differential equation to describe the data? I've attached the raw data...

I want to output a specific wavelength of infrared light, I believe the wavelength was 9.25nm, how hard would that be and how would I proceed?