Calculations Definition and 982 Threads

I am trying to calculate the forces in a system with a mix of conductive + dielectric components upon application of an AC potential. Frequencies are low enough that I need not consider magnetic field effects. I can solve equations to obtain the electric field, but at am a loss for force...

Hello All, Noobie question. I am using Meeus' Astronomical Algorithims to creat a spreadsheet to transform coordinates. I had no problem with precession, nutation, aberration, etc. But, I don't have as good a math background for Motion in Space. I can follow down to the final formulas for...

Hi, I'm currently studying my Quantum Mechanics notes from college last year and I've got to the bit about j-space calculations. The slide is very scant on details and google isn't yielding anything on this either. I would skip it but it seems important for deriving expressions such as...

Homework Statement Hi, well my task is to construct a DC motor. With 25w rotational mechanical output power. It cannot draw more then 5A current, and has to have 3 or more poles in rotation. The motor must be brushed/commutated. There is a max of 30v D.C. input. The motor needs to be built and...

Hai, I have the following circuit: http://img152.imageshack.us/img152/1848/powertransfer.png My task is to calculate the power dissipated in the resistor, and also the power delivered by the V1 source. Here's what i tried. First i /dev/null'ed the second source and calculated the...

My abstract algebra book is talking about reducing the calculations involved in determining whether a subgroup is normal. It says: If N is a subgroup of a group G, then N is normal iff for all g in G, gN(g^-1) [the conjugate of N by g] = N. If one has a set of generators for N, it suffices...

Hey. I am currently doing a bit of revision for an exam and I am struggling on the following question: I understand the whole voltage/current/power/impedance ratio stuff, but can't seem to find any information on calculating efficiencies using the resistances or the transformer core losses...

Homework Statement Calculate the integral Given \int_{C} \frac{e^z}{\pi i - 2z} dz = \int_{C} \frac{e^z}{z-\frac{\pi i}{2}} dz} using Cauchy integral formula. Homework Equations What I know \frac{1}{2\pi i} \int_{C} \frac{f(z)}{z-\zeta} = 2\pi i f(\zeta) The Attempt at a...

Homework Statement In using a ladder where the wall is smooth but the floor has a coefficient Us, why is it necessary to make the angle large? Homework Equations The Attempt at a Solution I'm a little confused by this, because I would think that you would want to make the angle...

Homework Statement An electron e^{-} and a positron e^{+}, each with a total energy of exactly 5000 MeV, collide head-on and annihilate to produce a tauon/anti-tauon pair, \tau^{-} and \tau^{+}, and no other particles. 1. For the electron moving before the collision, state or calculate the...

Homework Statement Example nuclear fission: {}_{92}^{235}U+{}_{0}^{1}n \rightarrow {}_{38}^{90}Sr+{}_{54}^{163}Xe+10{}_{0}^{1}n+Q How much energy does such fission release? Homework Equations I'm given the values of M({}^{235}U), m_{n}, M({}^{90}Sr), M({}^{136}Xe) but I've not...

Homework Statement The binding energy of a nucleus is given by: E_{b}=a_{1}A-a_{2}A^{\frac{2}{3}}-a_{3}Z^{2}A^{-\frac{1}{3}}-a_{4}\left(Z-\frac{A}{2}\right)^{2}A^{-1}\pm a_{5}A^{-\frac{1}{2}} For a given set of isobars, A constant, E_{b} will be maximised at the value of Z that satisfies...

Homework Statement {}^{241}_{95}Am produces \alpha particles, which interact with {}_{4}^{9} Be to produce neutrons. The Am sample emits \alpha particles at a rate of 70.0s^{-1} on June 16, 1996. What was the activity on June 16, 2004? Homework Equations The half life for...

A mass retaining wall having a vertical rear face is 0.4 m thick at the top and 0.8m thick at the base, is1.6m high and made of concrete of specific weight 24kN/m3. It holds back Earth with a specific weight of 18kN/m3 and an angle of internal friction of 20˚. The coefficient of friction...

Homework Statement Helicopter Noise Transmission [i]It is planned to introduce a regular helicopter service from a helipad at ground level in a hospital premises. There will be four arrivals and four departures per day but never more than one arrival and one departure in any hour. There is a...

Hello; I have never really come across vectors before in physics, so could someone help me out? For example, what would be an example question and a calculation involving this; \phi_m = \int \vec{B} \cdot d \vec{A} Correct me if I'm wrong but is this saying that the magnetic flux is equal to...

Hi, for a project at college i am building an ice hockey puck launcher for the development and training of ice hockey goaltenders. I am planning on using two wheels rotating in opposite directions to launch the puck. The pucks will be fed in by a pneumatic cylinder that is powered by a...

Hi, I'm working on a commercially available PEM fuel cell and I'm trying to calculate the theoretical voltage of the cell: The only electrochemical reaction considered is H2 + 0.5O2 --> H2O And I understand that I need to use the Nernst equation: E = EO - (RT / 2F) ln (PH2O / (PH2 *...

Homework Statement There is an unstayed mast which is 3m long, supported at the bottom and at 0.5m from the bottom. Sail area is 10 m^2, design wind speed is 50 km/h. It is made from glass epoxy composite. The base fiber is 300 g/m^2 glass textile. E-glass, 2/2 twill. The inner diameter...

Hi guys, I need to figure out the crushing force of a concrete crusher. Here's a pic to help illustrate: I have 2 questions: 1) Would the crushing force on the concrete be 2*Ft or only Ft and 2) Would the force exerted by the cylinder on each jaw be Fc/2 or Fc as shown. Thanks...

I am trying to self-teach myself Fortran for an undergrad research position. A basic program that I am trying to develop is something will open a file, read a single value from a large table of data, do some calculations with it, and print it into a new file. I was hoping to get a little advice...

Homework Statement a magnet that weighs 2.6 grams is dropped through a 1.53 metre tube. the average time taken for it to go through is 1.59 seconds. I need to find the strength of the magnetic field and the currentHomework Equations Fg=mg B=F/IlsinthetaThe Attempt at a Solution...

Homework Statement The Fourier transform of a function f(x) is given by the product of the Fourier transforms of cos(\alpha x) and e^{-|x|} ; f^{~} = F^{~}\left[cos[\alpha x]\right]F^{~}\left[e^{-|x|}\right] Find f(x) and show that it can be written as a real function. Note: Do...

Homework Statement Prepare 500ml acetic buffer with a concentration of 1 M and a pH o 6.0. (pKa for acetic acis is 4.76; molecular weight for actetic acid is 60g/mol and for sodium acetate is 136g/mol) Homework Equations The Attempt at a Solution I have tried the Henderson...

Suppose rabbit populations grow exponentially with a growth rate of 20% per year. If P(t) is the population at any time t and 1000 is the initial (t=0) population of rabbits, what is the population of rabbits in 10 years? Use the DE model: P ' = kP with k = .1 and P(0) = 1000. Plz help me

Heyhey, I am currently doing my final year masters project which involves testing rotor blades. I am performing a stress analysis of the blades. I will be using FEA software, but I also need to do some hand calculations. I have been looking for formulas for a while now, but I am unsure which...

So, like quite a few others on this forum, I am building a trebuchet for a school physics class. While I am really enthusiastic about the project (who doesn't love giant medieval war machines?), I may be a little bit over my head in the calculations. So I hope I can give enough information...

Homework Statement 1. Consider the point P at position ⃗rP = (−3.0 mm)ˆı + (4.0 mm)jˆ. Give an expression for rˆP , the unit vector in the direction of ⃗r. 2. Consider the point P from exercise 1 and another point Q at position ⃗rQ = (8.0 mm)jˆ. Give an expression for rˆPQ, the unit vector in...

Hey guys, I have been working on some calculations to help me with sniping in airsoft. I am working figuring out the angle of inclination I would need to hit targets at different ranges being only a rough outline (I am not too worried about getting into the various calculations such as for air...

Homework Statement 1 litre of a monatomic ideal gas starts from an initial state (i) at T = 300K and P = 10^5 N/m^2. It (the gas) is changed to a final state (f), such as that its pressure decreases 20% and its volume double. a) Draw a PV Diagram mark its initial state and final state...

Homework Statement A 4.9-µC point charge is located at x = 1.1 m, y = 3.1 m, and a -3.9-µC point charge is located at x = 2.1 m, y = -1.9 m. (a) Find the magnitude(inkN/C) and direction(in degrees) of the electric field at x = -3.2 m, y = 0.9 m. (b) Find the magnitude(in N) and...

Homework Statement I have been given the following load-displacement plots for the same specimin with two different crack lengths. The lines are identical up to a load od 750N i need to calculate the area of the blue shaded region to obtain a value of Jc using a separate equation...

Homework Statement an antelope moving with constant acceleration covers the distance between two points 70.0 m apart in 7.0 s. Its speed as it passes the second point in 15.0 m/s . a) what is its speed at the first point? b)what is the acceleration? Homework Equations what do you...

I'm currently studying physics at A-level, and for particle physics I'm fine about the theory of the equations, I remember what equations to use etc, but I can't seem to get the right answers from my calculator. For example, when working out the specific charge of a carbon ion with Z = 6, A =...

My understanding is that the folks who do particle mass calculations using the formalism of a lattice get results that fit measured values well without using a Higgs field. Is this correct? If so, do we have any use for and/or reason to believe in the Higgs field/particle?

Hi eveyone, I am working on project of designing a heat exhanger in order to recover heat from a exhaust of Stationary IC Engine producing power of about 2 MW. The fuel used for combustion is CNG. Most of the books I read, tells about the products that will be produced in exhaust after...

So there it is me trying to program some simple physics for flying ball. I have done some research and generally I was always understanding physics very well. But what is happening in my application is not understandable for me, even tho I have checked everything twice and I think everything...

I know this seems like a homework question but the last time I was in a physics class was <ahem> 1982. For product testing reasons, I have fabricated a (rough, very rough--no laughing at the fabrication/welding) 'repeating pendulum hammer'. Please see "test rig diagram.jpg" Distance from A to...

Hello all, This is my first forum post and any problems with the post are openly accepted. I would like a sanity check on my approach to this problem. I have built a permanent magnet three phase AC generator. I need help in properly calculating power values for this. This is for...

Ok, not really a homework question, just something I am confused about. Hopefully it belongs here. Alright this is in my lab book: The overriding consideration for significant figures in computations is that a result should not be quoted with a precision higher than the absolute...

this is a power calcualtion using 1 magnet pair with the turbine turning at 1 rpm..34 inch diameter rotor. i hope someone else can make sure I am at least doing it right, and i need help converting my single phase numbers to 3phase wye ________________________________________ coil info...

We were preparing Alkene from Alcohol & were asked to calculate percentage yield. We used 13.5 ml Cyclohexanol with 13.5 ml water & 7ml Sulfuric acid. To calculate % yield,i need theoretical mass.. So i was calculating no.of moles of cyclohexanol & cyclohexene (the product) to get the...

Homework Statement I'm trying to find the acceleration due to air resistance in x direction and acceleration due to air resistance +gravity in y component. given variables m-0.14273(baseball) Cd=0.4 Vi=20m/s angle= 45 degrees Basically, I have to program a projectile motion program...

I am usually bad with calculations, so please help me out. It's not a homework, merely my interest... So, let's say I have a tube with some air pressure in it and I open up one end of the tube so the pressurised gas exits it in one direction... (basically a rocket) Pretty simple, huh? :D...

Hi there, Had a fair bit of hoework my first day back with no answers. Would anyone mind looking over these to see if i did them correctly? Thank you for your time. http://img42.imageshack.us/img42/5117/46730937.jpg http://img35.imageshack.us/img35/4489/56478985.jpg...

i am trying to make a piece of stainless steel of varying thickness bend in such a way that it creates a cam profile in much the same way a fishing rod works. for example if the thick end has a 5mm by 10mm cross section and the thin end is 1mm by 10mm crosssection and the change in thickness...

I am looking to determine the temperature in a certain gauge wire, fed by a battery pack. I am looking to design the battery requirements and wire size in order to maintain a certain temperature. The electrical calculations (I am not an electrical engineer) I have found all assume continually...

Homework Statement Hi, I have a problem with the data and calculations part in my lab. For some reason, I can't get a molar mass of the given solutes to match my answer. I'll provide all the equations and my numbers. Please I really need help with this Homework Equations deltaT = m(kf)...

hi, im not involved into physics but i read sometimes about it and have very curious questions: Q1- if E=mc2 then as i know that electromagnetic waves have mass of zero so this mean E=0xc2 which means that c2=E/0 here i get that the E=0 , and c=infinite..which i guess is impossible so what...

Hi, I am a bit lost with AC circuits on the whole and could use some dumbed down explanation on the matter. Taking an example from course material: (Components connected in parallel. "Ladder connection") ------ l l l l l J C L R l l l l l ------ Where J = 1 (30 degrees)...