Calculation Definition and 1000 Threads

Hi. Is there a short way to calculate real integration? I tried it but it looks so tedious. I attached the question so please refer to that. I am stuck with no.1, by the way. Here is my attempt: ∫_0^(2π) dx/(13 - 5*sin(x)) let u = tan(x/2) which means x/2 = arctan(u) which means x =...

Hello, Been a while since I posted on here, nice to be back :) . I just want some pointers as to the methodology for an impact load case that I'm looking at. I've attached a very basic sketch of a trolley which is traveling at a known velocity and impacts a rigid structure at it's base. What...

As part of a physics calculation, I have the following integral $$\int d \bar x a^{\sigma} \left[-\partial_{\mu}\left(\frac{\delta x^{\nu}}{\delta a^{\sigma}}\right) (\partial_{\nu}\Phi )\frac{\partial L}{\partial (\partial_{\mu}\Phi)} + \partial_{\mu}\left(\frac{\delta x^{\mu}}{\delta...

Homework Statement If A is a time dependent vector, calculate [itex] \int_{t1}^{t2} dtA(t) \times \frac{d^2A}{dt^2} [\itex] Homework Equations The Attempt at a Solution I think we should somehow relate it with something's derivative. \int_{t1}^{t2}A(t)\frac{d^2A(t)}{dt^2}dt=...

Hello all, I have been working on an NPT monte carlo simulation. I would like to know how I can measure the instantaneous pressure of the system at each monte carlo step?

Hi, there. The following is copied from a book " atom-photon interaction " by Prof. Claude Cohen-Tannoudji, Page 415. I do not understand it at all. I do know some thing about the coherent state. such as ##a |\alpha\rangle = \alpha |\alpha\rangle## and ##|\alpha\rangle =...

Using the Hall-Petch relation, estimate the yield strength, σy, of a Cu-Zn alloy (brass) when the average grain diameter is 30 μm. where: σy = is the yield strength σ0 = 25 MPa is the internal friction stress ky = 12.5 MPa·mm1/2 is a material constant d = is the average grain size...

Hello, I'm attempting to calculate the magnetic field \mathbf{B} outside of a coil with current density, \mathbf{J}, and whose volume is a section of a sphere. Here is a diagram of the cross-section of the coil: (The wire ridges are aesthetic and aren't considered in the calculations - I'm...

I am designing a brake system for big reel that weighs about 2500lb, spinning down on a truck that is moving at 15mph, the shaft is 2.5inch in diameter. It is rotating at 53RPM and it comes to a stop at about 45 seconds. How do i start performing calculations and the design parameters...

1. Calculate the emf induced in ONE side of a coil of length 0.4m and width 0.3m, when there are 50 turns in the coil and the flux density is 96.8 mT, and the coil is rotated 30 degrees from the vertical. Frequency is 50 Hz and the long sides are the ones facing the magnets.

Hello all, As part of a research project, I am trying to calculate the amount of water/dry ice I would need to put in a cylindrical pressure vessel to obtain an internal pressure of ~100 psi at 200C (from room temperature, ~23C). I haven't had to do a calculation like this in awhile, but...

Homework Statement Suppose we have a container divided into equal halves. Right half is fixed at temperature ##T##, volume ##V_2##. Initially it has pressure ##P_0##, a hole of area ##A## is opened between them. Part (a): Show that the pressure in the right half is: p =...

could any guide me in Coolant Flow Calculation for finding heat rejection of engine through various system.

Hey y'all. I am working on a real application to the common textbook problem: fluid through a pipe with constant temperature wall. Find mean temperature profile of the fluid. In the textbook version, we assume the fluid is cold and it enters the hot walled region suddenly. We might also...

Hello i need to know what should i do, Consider i have a box, top half and bottom half. so now i have to hold the top half and bottom half together with the rubber band then how do i know what rubber band will be enough to exert force so that both parts of box are hold together. also i...

Homework Statement A very big iron plate with the thickness 2h have, far from the plates edges, had a hole with the radius a drilled through it. With respect to the holes axis of symmetry the plate has a magnetization \bar{M} = M_0 \frac{a}{s} \hat{s} where s is the distance from the axis of...

Homework Statement 2 1.2m nonconducting wires meet at a right angle. One segment carries +2.5*10-6 C of charge distributed uniformly along its length, and the other carries -2.5*10-6 C distributed uniformly along it. Find the magnitude and direction of the electric field these wires produce at...

Dear everybody here, Here is a problem to solve, from shigley handbook for Machine design, it's about Journal bearing design for the shown shaft in the attachment, i know how to design the journal bearing, but i am a little bit confused about how to get the reaction forces at the two points A...

For part a I have (H0-ω\hbarm)|nlm>, which I think the (H0-ω\hbarm) part is the eigenvalue of the Hamiltonian, also is the energies? And mainly, I am not sure how to approach part b, the time variable is not in any of the states. I saw this in our lecture notes: ψ(r,t)=∑Cnψn(r) e-iEnt/\hbar...

Homework Statement The period of Mars is 1.881 years. When Mars is opposite the Sun in the sky, its position with respect to the background of fixed stars is measured at sunset and again at sunrise. The effective baseline between the two positions is 11,700 km and the change in position on the...

Homework Statement vapour pressures of a liquid have been measured and fit to the following equation: Log10 (mmHg) = -3571/T + 6.124 The melting point has been determined to be 392.7 K. A Cp value given for the liquid is 250 J/mol K and theΔSvap is 117 J/mol K Homework Equations...

hello guys, i wanted to calculate inlet pressure of the pump( vacuum pressure). pump operates at 400 bar. pump works by sucking the grease from the inlet port of dia 7mm and delivers it through outlet port of dia 2.8mm. pump used here is piston pump. the force acting on the piston is 400bar...

Homework Statement This problem is regarding an oil suction pipe, pipe A is the the suction pipe and pipe B is the delivery pipe. There is a pump in between which supplies a head of 11.3m. The pressure in pipe A is atmospheric and the pressure in pipe B is 850kPa. The vertical...

It's part c I don't understand, why the expectation value equals to solid angle * sin3 i? I mean, what role does the solid angle play? Thank you

The problem is attached, and the official answer is given. The step in the answer does not make a lot of sense to me. How does the luminosity L converted directly into distance d, and why is the solar distance is used? And where does the dm=0.75 come from. It's just not making sense to me...

Hi, The following contains two questions that I encountered in the books of Claude Cohen-Tannoudji, "Atom-Photon Interactions" and "Atoms and Photons: Introduction to Quantum Electrodynamics". The first one is about how to calculate two Fourier transforms, and the second one is a example of...

Quick pH calculation -- Please verify A 50.0 mL aqueous solution of sodium hydroxide has a pH of 12.50. If 36.00 ml of 0.0200 mol/L sulfuric acid is added to this sodium hydroxide solution, what will be the new pH of the resulting solution? Assume that the temperature stays constant at 25C, and...

Hi, In my design there are PCB boards. But i am worried the thickness of PCB will not be strong enough to withstand cracking and warp-age when under stress and strain. Is there any formula i can use to calculate vibration on the PCB so i can increase thickness via mechanical ribs...

>According to http://www.chemguide.co.uk/physical/redoxeqia/introduction.html each electrode has an absolute electrode potential which is the difference between the positiveness and negativeness. So if we had a Zn plate in water and it has a negative charge of -5 on the metal. Would the absolute...

Homework Statement In Fig. 6.1 the distance from the two slits to the screen is 1.8 m. The distance CP is 2.3 mm and the distance between the slits is 0.25 mm. Calculate the wavelength of the light provided by the laser. Homework Equations $$asinθ = nλ$$ $$w = \frac{λD}{a}$$ The Attempt at a...

Hello guys, I have to make a short circuit calculation for school but I am a bit lost.. I have a copy off the IEC61363 and internet connection as my help lines. Homework Statement The network consists of a generator feeding to switchboard A with a cable in between, on the same...

For several years I have restored antique movie theater popcorn machines from the 1940's. I design and manufacture obsolete parts for these machines for restorers across the nation. I am currently prototyping a reproduction "popcorn stirrer flexible drive cable" and am in the process of building...

Hi Every one, I measured optical output power from both laser facets, front facets emits 120 mW and back facets 10 mW. Assuming front facets reflectivity of 30%(for cleaved facets). What will be the reflective of back facets? Please suggest formula and reference this problem.

Say I have a potential barrier that is 4eV higher then an electrons energy and 5x10^-11 wide. Just by considering the change in amplitude of the wave function from the entry into the barrier vs the exit I am asked to make a rough approximation for the probability of tunnelling. I get the...

1. The problem statement, all vbles and given/known data So I'm going throught the Nova Physics book and I'm wondering if there's a mistake in calculation. The question reads: How much volume does 0.4kg of oxygen gas take up at T= 27 degrees Celsius and P= 12 atm (gas constant R = 0.0821 L...

So this thread has been closed and I can't comment on it. I am working on this question as well and am stuck on b). I managed to solve for a) and c) but I have no idea how to go about finding the force normal and do not know where the formula "Fnet= mg + ma" came from or why to use it. Could...

Homework Statement I'm trying to calculate the integral: S= \int (d^{N}x) exp(x_{i} A_{ij} x_{j}) = (\frac{\pi^{N}}{detA})^{\frac{1}{2}} where the integration is done over (-∞,+∞) , and A_{ij}=A_{ji} (symmetric NxN matrix) Homework Equations The Attempt at a Solution I am not...

Homework Statement Calculate the pressure of sand grains falling on a 10cm X 10cm sheet of paper. Assume the grains are each 1 mg in mass, the ate pf the sand as it falls is 100 grains per second. The sane is falling from a height of 1m under gravity, and the sheet it falls to is sticky, so...

I would like to calculate the values for an air curtain. I've tried using the aircurtain calculator from Engineering Toolbox: http://www.engineeringtoolbox.com/air-curtains-d_129.html Δp = 2.2 q2 sin(α) / b H3/4 but I'm not sure how to figure in the length of the opening - q (q =...

Hello, I have a real world application that I need some help with. I am sensitive to the fact that this is not the space for homework questions, or homework style questions. I feel that this is neither. If you disagree, please let me know and I will post it elsewhere. It has been a while...

What is the funda behind the Elemental Composition Calculation of Cathode Material for Sodium / Lithium Ion Battery (Na2/3 Ni0.4 Mn0.4 Co0.2 O2)/ AMO2? Apart from the Oxidation state calculation, Phase Diagram Elimination of mixtures and Random Compistion, is there any Principle behind it?

Hello, How can one calculate the dimensions of valve shims in Gas pressure shock absorber? Desription- The valve shims are orifices to the fluid flow in the hydraulic damping system. The dimensions play a very vital role in the adjustment of compression and rebound of the damper. I have...

Hi I need to calculate the velocity of an airplane after it executes quarter loop (starts horizontally, pitches up and ends vertically). Because I also need to know the velocity at several intermittent points I wrote an incremental equation (below). But this is only correct (if it is correct...

hello, I was wondering how the atomic radii where calculated. I have used the formula r=\frac{a_{o}n}{z*/n*} where z* is effective nuclear charge and n* is the effective principal quantum number but it seems to give me a bit different radii compared to the ones on Wikipedia...

Given r, Δθ and Δz and ρ, Δφ and Δθ, I think that is possible calculate algebraically those regular surfaces without use integration. Is possbile? If yes, how?

I can compute the area of the rectangle formed by Δx and Δy simply by product ΔxΔy. Now, how can I to compute the area in gray given Δr and Δθ? Also, I can to compute the volume of a parallelepiped formed by Δx, Δy and Δz, simply multiplicand ΔxΔyΔz. But, how can I compute the volume...

Hello, i was wondering if the following is correct: The expected value of (a*x+b*x*y)/(c*y) given that a,b,c are positive constants and x,y are positive random variables is: ∫∫(a*x+b*x*y)/(c*y)*f_{x}(x)*f_{y}(y)dydx (where f_{z}(.) is the PDF of z). Thank you in advance.

The question is : A cable of circular cross-section and diameter 2 cm has a long cylindrical hole of diameter 1 mm drilled in it parallel to the cable axis. The distance between the axis of the hole and the cable is 5 mm. If the cable has a uniform steady current density of J=10 5 Am-2...

My company is working on a few concept ideas for our field. Currently we are looking at jump packs concept work. We are looking to lift a human about 180 pounds, and about 50-60 pounds of gear = 230 Pounds Total. Our goal is to lift that weight about 20 Feet in the air while the subject is in a...

Homework Statement I am trying to find value of a capacitor knowing capacitor impedance (Phasor) and ω (in rad/sec). The Attempt at a Solution Zc = -j/ωC C = -j/ωZc My question is do I have to convert the ω into degrees/sec before doing the calculations since Z(impedance) is in...