Beam Definition and 1000 Threads

Homework Statement In an inertial reference frame, a beam of light is shone 30 degrees from the x-axis. What is the speed of another inertial reference frame along the x-axis where the beam of light is 90 degrees from the x-axis? Homework Equations Can't really think of any equations that...

Homework Statement Just having some trouble with a question about Fabry-Perot intereferometers. Here's the question: a) Consider a beam of light undergoing multiple reflections in a Fabry-Perot cavity between two surfaces, both with reflectance R, and with no absorption. Homework Equations...

Hi, I'm trying to calculate bending stress for a cylindrical beam. I'd like to have my result double checked because I got an answer that doesn't make sense to me. All of this is personal research, so I'm not very confident in my answer. It's a cantilever beam with a point mass of 347.4 oz. on...

Homework Statement A photon beam is incident on a proton target (at rest). Particle X (and nothing else) with rest mass M=1.232GeV/c2 is then produced. Use m_p =0.938GeV/c2 as the proton mass. a) What is the energy of the photon beam, in terms of GeV? b) What is the momentum of the moving...

if a coherent laser beam rotates about an axis at very high angular frequency can a light dot with radiant glow (of short radius) be obtained due to persistence of vision ?

Would it be a drop in power as the square of the distance in a directed microwave beam? Thanks!

Homework Statement For the y-y axis buckling , the beam will bend towards either positive or negative y-axis , right ? I don't understand that why for y-y axis buckling , moment of inertia (Iy) about y-axis is used ? Homework EquationsThe Attempt at a Solution IMO , it's wrong ... When the...

To give a bit of context, I am doing my final year university project on micro-mechanical interactions between an AFM probe and a sample surface. I do not have notes for a system this complicated, as we always considered our systems to be rigid bodies. I was always relatively clueless at...

Homework Statement To give a bit of context, I am doing my final year university project on micro-mechanical interactions between an AFM probe and a sample surface. I do not have notes for a system this complicated, as we always considered our systems to be rigid bodies. I was always...

Hi there I have a general question. I understand the process of light through a optically denser material, slower speed etc... but why would a laser beam in oil be easier to "see" than a laser beam through water. Cheers

If the unbraced length of a beam is 3 m and the maximum bending moment in this unbraced segment is 312 kN-m, and also the maximum moment in the braced segment of the beam is 350 kN-m, select an economical section just based on the moment requirements. Use Table A.2M included in the course...

Homework Statement In this question, we are interested inthe buckling of column, so we should calculate the moment of inertia (Ixx) or (Iyy) at the column,right? Homework EquationsThe Attempt at a Solution Why the author calculate (Ixx) and (Iyy) using the cross sectional area of beam? is it...

Homework Statement in this question , ( in second photo) i don't understand that why at eccentricity ratio = 1 , P/ A is 83kPA , why the vertical line is drawn at a point between 100 and 150 KL/r to find P/A ? Homework EquationsThe Attempt at a Solution Is it wrong ? Or I left out something...

I have to calculate Airy's stress function for a cantilever beam made of two different material along its length. The young's modulus of the first half is E1 and E2 for second half. The beam is made such that these materials are joined to each other one after other along its length. At the...

Homework Statement I am trying to understand how forces transfer from a wheel / pulley onto a beam, and then calculating the resulting moment. The image describe the problem. The rope is in tension with force "S", the wheel/pulley can rotate freely without any friction. Homework Equations...

This is sort of SF in the sense that it's not scientifically accepted or reviewed. The "idea" comes from other people and it is that a usually round light beam of a certain diameter, like 30-50-100-similar cm diameter, extends slowly and even stops midair. It's flat at the end. Like a straight...

Can anyone help with calculating the starting and stopping torque required to rotate a uniformly laden beam with a total weight of 200kg around a fixed axis. The beam has a length of 2200mm and will be started from stationary, rotated through 70 degrees at which point it will stop and reverse...

Homework Statement where V = total shear force at the location in question; Q = statical moment of area; t = thickness in the material perpendicular to the shear; I = Moment of Inertia of the entire cross sectional area. based on this formula , the shear stress is max at the neutral axis of...

Homework Statement for the circled part, why the why the author didnt include -12(9)kNm moment in the equation of moment ? [PLAIN]http://imgur.com/a/l3Bu4http://imgur.com/a/l3Bu4 Homework EquationsThe Attempt at a Solution IMO, the author should include it in the equation, am i right? So, M=...

[mentor note: moved here from another forum, hence no homework template.] A construction worker attempts to lift a uniform beam off the floor and raise it to a vertical position. The beam is 3.00 m long and weighs 372 N. At a certain instant, the worker holds the beam momentarily at rest with...

I have a plate of 600mmX92mmx2mm. All the four sides are fixed.How can I calculate the effective deflection at the center due to self weight considering the deflection in longitudinal and transverse direction? Density of material 1170kg/m3 Modulus of elasticity 2.5GPa

Here I am only considering 4 adjacent electrons in electron beam, especially the 2 electrons that are moving in tandem with velocity v. Moving charge will generate circular magnetic current. you can imagine magnetic flux as current, just like electric current. So, the question is same to find...

Homework Statement I don't understand why the sign of moment of beam at left (clockwise) and moment at the right of beam (anticlockwise) are considered as positive... Why we can't assume the clockwise moment as positive and anticlockwise moment as negative? Homework EquationsThe Attempt at a...

Homework Statement in the first diagram , i notice that the moment is constant throughout the beam... why in the second notes, for the moment 20kNm at 2 ends of beam, why the moment varies from -20kNm to 0 from one end to another end? Homework EquationsThe Attempt at a Solution Which is...

Homework Statement http://www.mathalino.com/reviewer/mechanics-and-strength-of-materials/solution-to-problem-625-moment-diagrams-by-parts) from the link , why the distance of centroid from B is (4/3) and (9/4) as shown? Homework EquationsThe Attempt at a Solution it should be (4- (2/3) ) and...

Homework Statement for the first line of solution , i don't undertsand why the author only include one P/2 force only... Homework EquationsThe Attempt at a Solution I think it should be EIy" = 0.5Px -P(x-0.5L) -0.5P(L-x) , am i right?

Homework Statement In my notes , I was told that shear stress is maximum at the neutral axis . The normal stress will be maximum at one end , while the another end will be minimum... Homework EquationsThe Attempt at a Solution Why the shear stress is maximum at the neutral axis ? When we...

Homework Statement I have the bent beam like this . The inner part of beam undergo compression , right , so it shortens. Why the stress is minimum at here ? the outer part undergo tension , why the normal stress is maximum here ? This is from my notes http://imgur.com/a/H8fy4 Homework...

Hi all! I have to calculate the natural frequency of the system. Any idea of boundary conditions of this case? There is beam supported by two springs on the left side.

Homework Statement determine deflection of beam Homework EquationsThe Attempt at a Solution at x=0, y=0 , i found that C2 = LP(a^2)/6 (circled part) but the author gt 0, which is correct?

Homework Statement refer to the circled part , i don't understand the author's working . Homework EquationsThe Attempt at a Solution I think it should be 450x - 150(4-x) -30092)(x-1) , correct me if I'm wrong . (taking moment about x ) ...

Homework Statement can someone explain about the RHS of EIy' and EIy'' ? how to get the RHS of EIy" from RHS of EIy' ?? It's not integration of dx , am i right? Homework EquationsThe Attempt at a Solution if it's integration of dx, it should look like this , right?[/B] EIy' = 0.25P(x^2) -...

I am calculating the strain in a cantilever beam with a point load for a given deflection. The deflection is around .5mm for a beam that is just over 5mm long (width is 3.8mm and height is 0.15mm). I was told for the assumption of small deflections to be valid, deflection should be 2% of the...

Homework Statement A light ray falls from the air (##n_a=1##) into the center of the upper surface of a long cilindrical glass tube with an index of refraction ##n_t=3/2##. The tube is submerged into water all the way to the upper edge and the waters index of refraction is ##n_w=4/3##. What is...

I am trying to derive the strain at the base of a cantilever beam with a known deflection. I know the bending stress is equal to Mc/I, so the strain is Mc/IE, where c is the distance from the neutral axis. For a point load ,P, the strain would then be PL/IE. Since the deflection is known I...

I came to know that the PACS instrument of HERSHEL has a resolution of 5" at a scan speed of 20''/sec whereas it's 10'' at 60''/sec. The resolution has almost doubled with the scan speed. Can you please tell me why it's so?

What is the equation for how a light beam is bent by a mass? Say a mass M way out in space, and a light beam is aimed from VERY far away such that it should pass at a radius R from the mass.

Well, i have a cantilever beam where i have the displacement of the tip of the beam (y axis) data from a vibration of this beam. In the tip of the beam is a steel wire attached, pulling up the beam with an angle (30º for example). I want to know if exists a form to obtain the strain of the wire...

Hi, Well i have a system with a excited (in y axis) cantilever beam. I struggling to obtain a expression that gives the strain based on the dislocation y. I know that the displacement of the beam is given by: Ya=PL^3/(3EI) but how i make a correlation between this and the strain of the...

Hi Community, I have this question which I have been able to partially answer. Part 1: From samples, we measured the Flexure Modulus of a material and was asked to solve for the deflection of the material at a $1m$ span and $1kg$ which I used $$Maximum Deflection = \frac{wl^{3}}{48EI}$$ $W$...

The superposition of a gaussian beam and a plane wave generates a pattern of rings whose phase shift before and after the focal plane (of the gaussian beam) is ##\pi##. This means that if you measure interference before and after you'll see the minimums and maximums of intensity invert. We can...

Hello everyone, I am trying to find effect of collimated lens on gaussian beam propagation. Do you know how to solve that? I need any equations ,then going to use them via matlab. Thanks

Can the deflection curve of the beam in picture be solved by using the following approach: https://dl.dropboxusercontent.com/u/104865119/beam2.PNG 1) EI w''''(x) = q 2) Integrate four times, solve the constants from boundary conditions (deflection and moment zero at the supports) Thanks...

Some nuclides undergo decay of electron capture or beta plus. Can electron beam with appropriate energy accelerate electron capture beta decay? Same scenario: If I am looking for something, and my friend kindly hands it over to me, then I say thanks, because my seeking time is shorten.

Homework Statement A uniform beam at equilibrium is suspended by a cord at X which is 2m from one end of the beam and and 3m from the other end. There is a mass of 28N attached to the 2m end and a mass of 10N on the 3m end. Determine the weight force of the beam Homework Equations...

Hi, I thought it would be an easy one but it isn't... I am trying to solve the problem of a beam supported by three different springs with a uniform distributed load:

In mammography, an Mo anode is used because it produces characteristic X-rays at about 17-20 keV. Apparently, the ideal filter is also Mo. Why is this? Surely all the x-rays would just be re-absorbed by the filter? Thank you

Homework Statement If w = 74 kN/m , determine the absolute maximum bending stress in the beam in MPa. Homework Equations I'm not too sure how to go about my calculations. Please help! The Attempt at a Solution I = [(1/12)*(200*256^3)] - [(1/12)*(192*250^3)] = 29.62*10^6 F = 74*24*1000? [/B]

Homework Statement A uniform beam of mass m is inclined at an angle θ to the horizontal. Its upper end (point P) produces a 90° bend in a very rough rope tied to a wall, and its lower end rests on a rough floor (see figure below). Let μs represent the coefficient of static friction between...

Is the moment in a continuous beam maximum when there is one point load because if you had multiple point loads they would cancel each other out since there are several pin connections along the beam? For example, if I had a 20 kip load moving across a continuous beam and found the maximum...