Calculations Definition and 982 Threads

Hi, I am a PhD candidate doing some research on origins of field theory but my background is in E-field and power electronics and not astronomy. Looking for someone that might want to co-author a paper on the flyby anomaly or more specifically can help me check whether a prediction has any...

Would the efficiency calculated using the P output/P input x 100 get the same answer as calculating the efficiency using the RMS input and output values? If so why?

Would really be a big help if someone could look at my drawing and verify what I have come up with. Basically pulleys with cable wrapped around then and a weight hanging off the bottom. What I am interested in is what the wight pull at the pull scale would be and if their is any left or right...

I would like the formulae for calculating the distance created bewteen products transferring from one conveyor to another with a line of products moving at x M/min transferring onto a conveyor running y M/min. I need to be able to calculate what the gap will be between the products as this is...

Hello Everyone, I am a PhD student working in the field of mineral and material processing. One part of my project involves use of DFT calculations to study adsorption of small to mid sized molecules on mineral crystals. I am using Gaussian 09 simulation package and currently I am in the...

me and my partner did an experiment of turning copper coins into 'silver' and 'gold' we used this site or the info: http://www.nuffieldfoundation.org/practical-chemistry/turning-copper-coins-silver-and-gold But we're having trouble with knowing how to make the calculations of : How much...

hi, i have some problems in power train calculations for a small race car has a chain instead of crank shaft converting motion to the rear side, calculating torque on the axle and wheels, forces and the acceleration of the car. So, can anyone help or mention a guide reference ? thank you

Im working on a little project where I am attempting to generate steam from a hot gas pipe. I haven't measured the rate of flow or temperature of the fluid as of yet, and I haven't decided upon the choice of material, but I'm looking for some calculations to start. My plan is to wrap a water...

I want to make sure I understand what I am reading in various spec sheets when they quote their noise measurements and I hope that you-all can confirm that I am on the right track. Take the OP27 Op-Amp as an example, which is described as a low-noise precision operational amplifier...

Hi Guys : I have been reading about torque and gears and not being an engineer or physicist would like to know if my thinking is correct in the following example Ok so Say I have a hydraulic motor and it generates 3000 ft lbs of torque and it is going to be turned at 650 RPM (tractor...

Homework Statement I've been following closely a book on PDE's working through lots of steps but here I'm stuck. Basically I have the relation f(x)= \sum _{n=1}^\infty F_n \sin \left ( \frac{n\pi x }{L} \right ). I want to calculate the Fourier coefficients F_n. I look at the definition in...

Homework Statement I am in a beginner c++ class and this is my second program. I am having trouble getting the calculations to output correctly. I'm not sure what I'm doing wrong here, maybe somebody can help. Homework Equations The program takes user input data for points in a...

Hi, How do I develop and train to do quick back of the envelope calculations? How have you developed these techniques? I am not quick in it and make silly mistakes.

Im about to hand coursework in. Its the youngs modulus of copper wire We added 100g weights and measured the extension using a traveling microscope. for example at 0.900kg the wire extended by 6.36cm my calculations are Diameter = d 2.7x10-5 m Cross section area A = Pi x d...

Lets assume that all properties of a piece of piezoelectrical material are known, how should the analytical calculations be performed if the goal is to convert a vibration into electrical energy? What I'm looking for is the theoretical output voltage one can achieve for a known vibration. To...

Homework Statement Find nonzero scalars a, b, c, such that au+b(u-v)+c(u+v)=0 for every pair of vectors u and v This isn't a homework question, more of a conceptual exercise, but I want to understand it thoroughly.The Attempt at a Solution I've gone to u(a+b+c) + v(c-b)=0 then I couldn't quite...

If I take the Dot Product of two vectors, say A and B, I get: AxBx + AyBy + AzBz And then when I add those terms, I get the magnitude, right? So when one of those terms are negative, that means I could end up with a negative magnitude? I thought magnitude had to be positive.

i want the gear so the car is going 100 mph at 6000 rpm 1:1 drive at end of 1/4 mile. have figured out this much for dry run. 32 inch DIAMETER tire x pi 3.14 = circumference. let's call it 100 inches. one mile is 5280 feet. engine will turn at 6000 RPM. RPM is in minutes. MPH is in hours...

Homework Statement Calculating focal lengths of lenses. s = 144.7 ± 5.52 mm s' = 86.0 + 0.71 mm Homework EquationsFocal Length f = (s)(s') / ( s + s' ) Adding/Subtracting two numbers with uncertainties A + B ± root [ (±A)^2 + (±B)^2 ] Multiplying/Dividing AB ± root [ (±A/A)^2 + (±B/B)^2)...

From what I recall, determining the focal length of a double convex lens just involves an infinite light source and holding the lens close to an image-capturing surface such as a wall and adjusting the distance until the image is at its sharpest...the distance from the lens to the surface is the...

Hi, I am trying to calculate weight transfer from the front to rear of a vehicle and have already calculated the total sprung weight to be transfered. I now need to calculate the Roll resistance generated by the springs using the following forumula and this is where the error occurs...

Hello, I am trying to determine the calculation to use to determine the force at which a disk plate will fail for the following set up. The disk is slid onto a metal bung for a roll, the disk is supported from the inside diameter for around 50mm. A force is then applied on the oppsite side...

[FONT="Times New Roman"]Homework Statement Find impedance and Io. draw phasor diagram for rlc circuit V = 120cos(2π525t) where R = 10Ω, C = 1μF, L = 100mH, Vo = 120V Homework Equations Z = √(R2 + (ωL-1/(ωC))^2) = √(10^2 + (2π * 525 Hz * 100 mH - 1/(2π * 525 Hz * 1 μF ))^2) = 28.525Ω...

I have values of time, and volts of a noise signal. I am trying to determine the noise power, signal to power ratio and bit error probability. How would I go about doing this? Thanks.

y=\frac{100}{100}\frac{\frac{(((100/100)^2-100*100)e^{x/(100*100)}+(100*100))e^{-x/(100*100)})-(100/100)^2e^{-x*100/100}}{100/100-100*100}}{1} http://www.quickmath.com/msolver//graphs/2011-12-06/e5/61/e2/e561e26ac85a4b1da0176565a4827772-2.png?t=1323201139 0 0 1 3.67866E-05 2 0.000113525...

I am trying to understand how calculate the forces in the beams or atleast how they relate to each other. There is a pin at the top right its just hidden as it is a wheel behind the rail. I am confused at the pin where the cylinder connects on how the load would be transferred to the lower parts...

This isn't really a homework problem, more of a "I'm-building-something-and-need-to-make-sure-the-physics-are-right-before-I-build-something-impractical" problem. Homework Statement Homework Equations The Attempt at a Solution (I grouped it all together, easier for me to not separate each...

Homework Statement Ok, for my Mechanical engineering class we have been assigned to make a 2ft ^3 5kg device that will launch a tennis ball 20-40 ft. My group decided to use a design more or less like a crossbow, so I was hoping someone would look over my calculations and make sure they're...

I have been given the masses of 5 cups, each with a different amount of screws inside. I am asked to find the mass of a single screw. The cups themselves are all equal in mass and the screws are all equal in mass as well. I subtracted all the cups from each other to get a bunch of numbers...

How can we calculate phase voltages from the line voltages when the 3-phase system is unbalanced?

hi every one. i am struggling with the same problem. my principal stresses were the same as the guys above but my von mises σyeild=325MPa which is also smaller than the tresca hexagon σyield =421 MPa. von mises = σ1^2+σ2^2-σ1σ2=(σyield/K)^2 i was wandering if this method was correct p.s. is...

We studied the reactions NH4Cl(aq) → NH4(aq) + Cl (aq) and NH3(aq) + HCL (aq) → NH4Cl(aq) in lab today, and part of our assignment was to give the formation reaction by first calculating the neutralization part ΔH of our lab and the solution reaction part ΔH of our lab. We were given this...

I am trying to program some motion control devices which have trapezoidal motion profiles to define a move. I can define the slewing(peak) velocity, accel/decel rates and distance to travel, the the hardware moves a motor the appropriate distance with the parameters given. I need to be able...

I have some trouble with the calculation of energy in magnetostatics, using the vector potential A. From the classic formula that uses B*H, I find the expression (in magnetostatics) in terms of A and J (current density): \begin{align}W &=\frac{1}{2}\int_V{\vec{B}\cdot\vec{H}{\rm d}V}\\...

A 73 kg trampoline artist jumps vertcally upward from the top of a platform with a speed of 4.8 m/s. a) What is his speed as he lands on the trampoline, 2.6 m below his jump off point? Express your answer to 2 significant figures. = 8.6 m/s (already figured out this to be the correct...

I think I'm over thinking this, so someone set me straight. If I have an eletric motor with a 75mm OD shaft making 1450Nm of torque, and I add a 7in pulley/sheave to the motor shaft. Would the torque change? Half of me says yes other half of my brain thinks no. Torque = Force *...

I was watching a show the other night about the Large Hadron Collider, and I got to wondering how much force it would take to push two uranium nuclei right up against each other. I figured it would be on the order of a thousandth, maybe a millionth of a pound, which seems like a lot, considering...

Homework Statement Electromagnetic Railgun consists of two parallel, distant from the horizontal, very long rails, after which moves perpendicular to the rails, linking them to the metal bar of mass m. The rails are in a vertical magnetic field intensity B. What is the speed limit the...

Homework Statement A vehicle weighs 3000 lbf and has an initial velocity of 68 mph. If the braking system is designed to stop the vehicle at constant power, calculate the stopping distance in feet, if the stopping power is 100 hp. m = 3000 lbf / 32.2 ft/s2 = 93.17 (lbf-s2)/ft v = 68 mph...

Homework Statement Light with wavelength 452 nm illuminates a surface. The work function of the surface is 5.77 electron volts. 1. What is the frequency of light hitting the surface? 2. What is the maximum kinetic energy of the electron ejected from this surface? 3. What backing...

Hi guys This is my first post here. I studied physics about 15 years ago and some weeks ago I realized that I'd forgotten most of it. So these days I'm playing around with physics just for the fun of it. So, I got to the subject of heat transfer, and though I would like to learn some more...

Question on calculating gravitation per General Relativity and the field equations: I understand that Einstein's field equations describe spacetime. But I’m not sure of how they are used when evaluating gravitation. For example, the equations describe how spacetime is “curved” by a large...

Please check if my solutions are correct or if I am totally wrong. Thank you! 1. Homework Statement [/b] In an experiment to measure the density of a steel ball. The diameter of the ball is d= 1.76 +- 0.02 cm and the mass to be m= 22 +- 1g. (include error calculations and report values with...

I am having a lot of difficulty calculating the cross-sectional areas necessary for normal/shear stress problems. If the cross-section is a square or circle, I'm fine, but when the problem makes a diagonal section through the object I get really confused on which angle/trig function to use to...

What programs model nuclear reactors and can determine if the reactor goes critical or not? It would be a big advantage if the given programs are open source as well, since the ones that cost money evidently cost a lot. I might be able to get hold of SCALE 6.1, but that program/code would be...

Homework Statement 1,035m^2 / 42m What unit will I use? m or m^2 Homework Equations The Attempt at a Solution 25.0m

Homework Statement I am given a resistor, 40KΩ + or - 20%. I know the uncertainty formula but it involves two variables, but not how to combine these together to get an answer. Not to mention, isn't the uncertainty formula redundant since I know the 20% over or under? Homework Equations...

from what I know: cross section in particles physics can be seen as throwing random darts on ballons on a wall, ie the wall is stationary. but if I want to work out the cross section of two laser beams at certain angles, the analogy above wouldn't hold would it? Since photons can never to...

Hey, this is my first post ever on PF, and I have done my best to follow the guidelines on posts asking for help with homework. Please know that I am not after the answer just to cheat and get the questions right, I am after the method so that I could do a similar question myself in the future...

Hi, I have a very basic question. Theoretically,I need to make a load hover (in real terms I'm makin a heli). I wanted to do the calculations for how much power is needed by the prime mover (engine/motor doesn matter) to hover. i.e to give thrust(T) = weight of (load+Motor). Can someone...