Calculations Definition and 1000 Threads

A calculation is a deliberate process that transforms one or more inputs into one or more results. The term is used in a variety of senses, from the very definite arithmetical calculation of using an algorithm, to the vague heuristics of calculating a strategy in a competition, or calculating the chance of a successful relationship between two people.
For example, multiplying 7 by 6 is a simple algorithmic calculation. Estimating the fair price for financial instruments using the Black–Scholes model is a more complex algorithmic calculation.
Statistical estimations of the likely election results from opinion polls also involve algorithmic calculations, but produces ranges of possibilities rather than exact answers.
To calculate means to determine mathematically in the case of a number or amount, or in the case of an abstract problem to deduce the answer using logic, reason or common sense. The English word derives from the Latin calculus, which originally meant a small stone in the gall-bladder (from Latin calx). It also meant a pebble used for calculating, or a small stone used as a counter in an abacus (Latin abacus, Greek abax). The abacus was an instrument used by Greeks and Romans for arithmetic calculations, preceding the slide-rule and the electronic calculator, and consisted of perforated pebbles sliding on iron bars.

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  1. A

    Automotive 100 MPH/Rear Gear 1/4 Mile Drag Calculations

    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...
  2. X

    Large Uncertainty Became Unsignificant After Calculations?

    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)...
  3. A

    Focal length calculations for a double convex lens?

    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...
  4. J

    Roll resistance calculations error?

    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...
  5. B

    Stress calculations on a disk plate

    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...
  6. X

    Rlc problem: calculations of components and phasor drawing

    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 Io = Vo/Z = 120 V /...
  7. V

    Calculating Noise Power, SNR, and Bit Error Probability

    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.
  8. K

    How can I avoid large exponents in calculations with small answers?

    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...
  9. K

    How Do Forces Transfer in Scissor Lift Beams?

    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...
  10. J

    Verifying Physics Calcs for 25k RPM Motor/Flywheel

    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...
  11. R

    Tennis ball crossbow calculations

    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...
  12. J

    Finding mass of a single screw lab No calculations XD

    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...
  13. A

    Phase voltages from line voltages calculations

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

    Von mises smaller than tresca in calculations

    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...
  15. R

    How Do You Calculate the Formation Reaction ΔH Using Hess's Law?

    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...
  16. L

    Trapezoidal motion/kinematics calculations - solving for slewing velocity

    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...
  17. M

    Vector potential and energy calculations in magnetostatics

    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}\\...
  18. K

    Trampoline Artist Jumps: Speed & Spring Stiffness Calculations

    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...
  19. X

    Statistics - bivariate density calculations

    Homework Statement Consider the bivariate density f(x,y)=c(x+y) for 0<=x<1, 0<=y<1 a) Obtain the appropriate normalization constant c. b) Obtain the marginal densities for X and Y, and calculate their means and variances. c) Obtain the covariance between X and Y, and check whether the...
  20. M

    Pulley Torque Calculations for Motor with Added Pulley: Is the Torque Affected?

    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 *...
  21. F

    Are these two calculations of electrostatic force correct?

    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...
  22. P

    Electromagnetic Railgun - calculations

    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...
  23. E

    Automotive Engineering, Stopping Distance Calculations Help?

    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...
  24. N

    Photoelectric effect calculations

    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...
  25. P

    Calculations of heat transfer in a tank system

    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...
  26. C

    General Relativity Gravitation Calculations

    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...
  27. M

    Please check solutions to Error Uncertainty calculations

    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...
  28. P

    Cross-sectional area for stress calculations

    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...
  29. V

    Programs/codes for criticality calculations

    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...
  30. V

    What Unit Should Be Used in Division of Meter Squared by Meters?

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

    Physics Uncertainity + resistor calculations

    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...
  32. wukunlin

    Photon-Photon Scattering: Cross Section Calculations

    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...
  33. D

    Resistors in Series Calculations including Uncertainties

    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...
  34. R

    Power calculations for Hovering

    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...
  35. M

    How can I calculate eddy currents in a changing magnetic field?

    I searched a lot of google for calculations on eddy currents, and got a lot of things that describe how eddy currents work, but almost nothing about how to quantify the induced currents and the resulting magnetic field. Does anyone here know much about where to start? In particular, I'm...
  36. M

    Horizontal water rocket thrust calculations - HELP

    Horizontal water rocket thrust calculations - HELP! Hi All, I want to accelerate a 90kg body at a rate of 2 m/s2 for a period of 1 second using thrust developed from a number of water bottle rocket jets. Based on the drag coeff calculated I believe I need to develop 190N of force. A...
  37. F

    Is there a more accurate way to calculate lift force in aerodynamics?

    Hi, I'm right now coursing IB (equivalent to A-levels) and one of the compulsory essays we must do is called Extended Essay. It's an essay you do on a topic you choose. I choose aerodynamics. Created a "wind tunnel" out of plastic and made it rigid with hard plastic pieces which were partially...
  38. J

    Error propagation in calculations

    This is an issue I am running into at the beginning of my physics course. Homework Statement Given distance and time in minutes, calculate the time in hours (part of a larger average velocity question) and graph over 170minutes. Include error bars in the graph Homework Equations...
  39. M

    Simple Calculations for Information on a Car

    I just bought a new car, nothing incredibly special. And being a nerd, I love creating theoretical calculations based on given data. So, I've been trying to predict the effects on my car under certain scenarios. I am doing my best to figure out the effects based of equations alone, and not...
  40. B

    Vector field calculations- dumb question

    Given 2 vectors, say x and y with a relationship of barXx-barYy (barX =1,0,0 and barY=0,1,0) calculations for the vector field in x and y plane are: Magnitude = sqrt(x2+y2) tails of vectors begin at input points (IE: if I choose 1,0 or 0,-1 etc) and the magnitudes are calcluated from these...
  41. J

    Surface Area Calculations in AutoCAD

    My problem: I calculate, using Differential Geometry, the surface area of a specific part to be 50% more than the surface area AutoCAD calculates it to be using the AREA command on an extruded solid. I am certain that my calculations are correct. I use theorems of Differential Geometry that...
  42. Femme_physics

    Moment of inertia: Answer without calculations

    To this shape http://img10.imageshack.us/img10/2301/nocalculations.jpg Uploaded with ImageShack.us I'm asked to calculate the estimate of the static moment of inertia of the planar shape towards the x axis, that goes through its center of gravity. And then I'm told that I'm asked for...
  43. N

    Calculations with Weyl Spinor Indices in QFT

    Homework Statement The task is to show the invariance of a given Lagrangian (http://www.fysast.uu.se/~leupold/qft-2011/tasks.pdf" ), but my problem is just in one step (which i got from Peskin & Schröder, page 70) which i can not reproduce due to my lack of knowledge regarding spinors. The...
  44. K

    Noise Power Calculations in dB or dBm

    The ourput Noise Power is given as No = kTsBG + kTeBG ...= k.(Ts+Te).B.G But when it is asked in dB or dBm, How to calculate it something like 10Log10(Value) or 20Log10(Value)
  45. T

    What Motor Size Do I Need for My AAV Track System?

    I am a freshman mechanical engineer and I do not believe that I have taken enough physics or statics to accomplish this task in a timely and correct manner. I am an intern at a government contracting company and am building a model of an AAV track system to test different coatings on. I need...
  46. I

    [NEED HELP ] Linear Systems Calculations

    Hi guys/gals, First post here - in need of some desperate last minute help. Today is my last day to study and I will have my final exam tommorow. I've been doing past papers all day, and there a few questions I have no idea/never seen before in my course material. Part (c) I have no idea what...
  47. A

    Magnetic Field Mass Spectrometer Calculations

    Here's a practice diploma question I found on the internet, this isn't homework. I'm studying, I just need help on how to do this type of question. http://www.paulway.com/physics30/p30dips/p30jan2002.pdf (Page 11 Numerical Response #5) Answer: 4.80x10^-3 Homework Statement In the magnetic...
  48. M

    Combustion calculations and the required amount of air

    I'm working as an intern at a factory that produces refractory bricks, mainly doing measurements on a tunnel kiln they use for firing the bricks. The bricks are heated with several natural gas burners in a firing zone. To determine the required air for both stoichiometric and excess-air burning...
  49. U

    Travelling to a Star 40 Light Years Away: Time and Distance Calculations

    A star is 40 light years from Earth. (a) How far would you measure this distance to be if you traveled it in a spaceship moving at 1.00X10^8 m/s (b) How long would the trip last (for you)? Can someone please help me out with this question and what equations I should use to solve this...
  50. P

    Calculations of Significant Figures

    A rectangular plate has a length of (21.3\pm0.2) cm and a width of (9.80\pm 0.1) cm. Find the area of the plate and the uncertainty in the calculated area. Solution Area = lw = (21.3\pm0.2 cm) X (9.80\pm0.1 cm) \cong(21.3 X 9.80 \pm 21.3 X 0.1 \pm 0.2 X 9.80) cm^2...
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