Formula Definition and 1000 Threads

In science, a formula is a concise way of expressing information symbolically, as in a mathematical formula or a chemical formula. The informal use of the term formula in science refers to the general construct of a relationship between given quantities.
The plural of formula can be either formulas (from the most common English plural noun form) or, under the influence of scientific Latin, formulae (from the original Latin).In mathematics, a formula generally refers to an identity which equates one mathematical expression to another, with the most important ones being mathematical theorems. Syntactically, a formula(often referred to as a well-formed formula) is an entity which is constructed using the symbols and formation rules of a given logical language. For example, determining the volume of a sphere requires a significant amount of integral calculus or its geometrical analogue, the method of exhaustion. However, having done this once in terms of some parameter (the radius for example), mathematicians have produced a formula to describe the volume of a sphere in terms of its radius:




V
=


4
3


π

r

3




{\displaystyle V={\frac {4}{3}}\pi r^{3}}
.Having obtained this result, the volume of any sphere can be computed as long as its radius is known. Here, notice that the volume V and the radius r are expressed as single letters instead of words or phrases. This convention, while less important in a relatively simple formula, means that mathematicians can more quickly manipulate formulas which are larger and more complex. Mathematical formulas are often algebraic, analytical or in closed form.In modern chemistry, a chemical formula is a way of expressing information about the proportions of atoms that constitute a particular chemical compound, using a single line of chemical element symbols, numbers, and sometimes other symbols, such as parentheses, brackets, and plus (+) and minus (−) signs. For example, H2O is the chemical formula for water, specifying that each molecule consists of two hydrogen (H) atoms and one oxygen (O) atom. Similarly, O−3 denotes an ozone molecule consisting of three oxygen atoms and a net negative charge.
In a general context, formulas are a manifestation of mathematical model to real world phenomena, and as such can be used to provide solution (or approximated solution) to real world problems, with some being more general than others. For example, the formula

F = mais an expression of Newton's second law, and is applicable to a wide range of physical situations. Other formulas, such as the use of the equation of a sine curve to model the movement of the tides in a bay, may be created to solve a particular problem. In all cases, however, formulas form the basis for calculations.
Expressions are distinct from formulas in that they cannot contain an equals sign (=). Expressions can be liken to phrases the same way formulas can be liken to grammatical sentences.

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  1. C

    Calculating Shear Stress in Beams: V and A Formula

    Homework Statement in the old thread , i was told that The formula for calculating the shear stress is a beam is ##τ = \frac{V ⋅ Q}{I ⋅ t}## τ - shear stress V - shear force Q - first moment of area above the location where the shear stress is calculated. I - second moment of area for the...
  2. KishoreAM

    Calculating Internal Pipe Diameter: What's the Formula?

    Guys...need a little help Given Internal fluid Pressure P (Not Pressure Drop) flow rate Q Length Assume all the required parameters like viscosity, fluid density, temperature of the fluid, surface roughness and all losses (both major and minor) etc... I need to find the internal diameter of...
  3. synMehdi

    Automotive Formula 1 Traction Control tuning

    Hello, I'm a mechanical engineering student and I'm working in traction control for Formula 1 cars. The traction control in the cars is simple, too simple: an engine cut is done when the engine is at a certain RPM and slip value. A matrix of four values of RPM and slip has to be provided to...
  4. P

    I Scale factor/redshift formula wrong at the end?

    In this video: The professor at the end (at about 7:28), used the formula for scale factor and redshift as a(t) = 1/z, instead of the actual one a(t) = 1/1+z. And when we apply both of them, they give very different results. So, how could the professor use the first formula, which we were...
  5. S

    How to Use Vieta's Formula for Finding Roots of a Polynomial?

    Homework Statement Part (b) Homework Equations Vieta's formula The Attempt at a Solution Part (a): I'm kinda stuck on part (b) - I tried multiplying the product of roots and got b^2 d^2, but I have no idea on dealing with the sum of roots.
  6. H

    I General formula for centre of mass of polygons

    The position vector of the center of mass of a triangle is ##\frac{1}{3}(\mathbf{a}+\mathbf{b}+\mathbf{c})##. Is the position vector of the center of mass of a planar four-sided figure ABCD ##\frac{1}{4}(\mathbf{a}+\mathbf{b}+\mathbf{c}+\mathbf{d})##? Does this generalise to n-sided figure...
  7. R

    Is Chromoly the Ultimate Material for Racing Car Chassis?

    I am in search for journal articles/papers regarding the use of chromoly (41xx) or HSS tubes in racing car chassis (space-frame) for a literature review. I wasn't able to find any papers up till now. Any help is greatly appreciated.
  8. MelissaBlaze

    How to Calculate Peak Speed and Time Dilation for a Relativistic Spacecraft?

    Hi, If I want my spacecraft to accelerate at a rate that produces 1 G for a set distance (half way to another solar system) then decelerate at the same rate for the second half of the trip, what formula would I use? I would like to calculate the peak speed of the ship and the time dilation...
  9. C

    Magnetic Field outside an Iron Core Solenoid

    I need help in calculating the magnetic field outside of an iron core solenoid at different distances. I have made an electromagnet by taking a 99.99% pure iron (5cm in length and 1 mm in radius) and wrapping wire over it. I have measured it's magnetic field at the end and cannot find an...
  10. E

    I Planck formula and density of photons

    Hello! Let's consider again a system of atoms with only two permitted energy levels E_1 and E_2 > E_1. When electrons decay from E_2 level to E_1, they generate a photon of energy E_{21} = E_2 - E_1 = h \nu. The number of photons (per unit frequency, per unit volume) emitted by such a system in...
  11. Dj Pedobear

    How can I solve this without using Reduction Formula?

    Homework Statement integral of cot^2 x / csc^8 x dx Homework Equations u = cot x du = csc^2 x du The Attempt at a Solution if I use reduction formula I could answer this but it's going to be very very LONG SOLUTION I just need some basic integral work.
  12. C

    Calculating Shear Stress: Understanding the Role of Y in Shear Force Diagrams

    Homework Statement Refer to the second photo , Q= Ay Does the author mean point P is at the center of the region (62.5mm x 100mm) ?The figure is not labelled well i am confused Homework EquationsThe Attempt at a Solution In the notes , I was told that y is the location of the shear stress is...
  13. T

    Chemistry Molecular formula of organic compound

    Homework Statement Homework EquationsThe Attempt at a Solution Firstly I tried to find the empirical formula: C : H : O 65.2 : 8.75 : 26.05 (mass) 5.43 : 8.75 : 1.628 (mol) 3.34 : 5.37 : 1 10 : 16 : 3 C10H16O3 This gives a molecular mass of 184. Now with the structure: It has to...
  14. K

    Help explain the following formula? (Young's doubles slit)

    Hello, I'm currently writing a report on young's double slit experiment, and I've used the equation nλ/d = x/L and I was wondering if someone could explain the question? I know how it works, and how to solve for lambda, but could I have some more detail into why it works? For example, why can...
  15. alaa amed

    Rationalize the numerator of your formula?

    Homework Statement (b) Rationalize the numerator of your formula in (a) to rewrite the expression so that it looks like f(h)/g(h), subject to these two conditions: (1) the numerator f(h)defines a line of slope -1, (2) the function f(h)/g(h) is defined for h=0. When you do this Homework...
  16. maxhersch

    I Find the formula to express the infinite series....

    The problem is to find the general term ##a_n## (not the partial sum) of the infinite series with a starting point n=1 $$a_n = \frac {8} {1^2 + 1} + \frac {1} {2^2 + 1} + \frac {8} {3^2 + 1} + \frac {1} {4^2 + 1} + \text {...}$$ The denominator is easy, just ##n^2 + 1## but I can't think of...
  17. F

    Mohr's Circle Formula: Understanding Why σ_xl Disappears

    Homework Statement https://web.iit.edu/sites/web/files/departments/academic-affairs/Academic%20Resource%20Center/pdfs/Mohr_Circle.pdf[/B] why will σ_xl disappear in the equation ? [ [σ_xl - (σx -σy)/ 2 ] ^2 ] = ( [ (σx -σy)/ 2] ^2 ) is it wrong ? Homework EquationsThe Attempt at a...
  18. J

    I Can Kirchhoff's Formula Be Verified by Substituting Back into the Wave Equation?

    I've read the derivation of Kirchhoff's formula for three dimensional wave equation using the Euler-Poisson-Darboux equation. The derivation seems to be fine, but I thought that the Kirchhoff's formula as a final result is a kind of result that you should be able to verify it by substituting it...
  19. H

    I Does derivative formula work for all parametric equations

    The derivative for the parametric equations ##x=f(t)## and ##y=g(t)## is given by ##\frac{dy}{dx}=\frac{\Big(\frac{dy}{dt}\Big)}{\Big(\frac{dx}{dt}\Big)}## The proof of the above formula requires that ##y## be a function of ##x##, as seen in...
  20. lsepolis123f

    What is the car leasing calculation formula

    Homework Statement // given in JavaScript var amount = parseInt($('input[name="amount"]').val()); var downpayment = parseInt($('input[name="downpayment"]').val()); var interest = parseInt($('input[name="interest"]').val()); var months = parseInt($("#months").val());Homework Equations What is...
  21. S

    Calculate y^(p+q) using the Leibniz formula

    Homework Statement Statement:[/B] Let y = u(x)v(x). a) Find y' , y'', and y''' b) The general formula for yn, the n-th derivative, is called Leibniz’ formula: it uses the same coefficients as the binomial theorem , and looks like https://i.gyazo.com/53728964c6b3ef142fd70f600c29e037.png Use...
  22. H

    I Derive the formula for gradient using chain rule

    Consider a surface defined by the equation ##g(x, y, z)=0##. The intersection between this surface and the plane ##z=c## produces a curve that can be plotted on an x-y plane. Find the gradient of this curve. By chain rule, ##\frac{\partial y}{\partial x}=\frac{\partial y}{\partial...
  23. E

    MHB Formula for calculating DPS (damage per second)

    I am calculating damage per second (DPS) for a character in a video game. This character strikes twice every 4th attack. (Doublestrike) This extra strike does 50% of your attack damage. This extra strike, along with all other strikes, can crit, meaning meaning they do twice the damage. My...
  24. F

    Solving Formula of Forces Homework

    Homework Statement from the notes , the author stated that force has the formula of ρ(L^2)(v^2) and also = ρ(L^3) i think there's something wrong with the ρ(L^3) Homework EquationsThe Attempt at a Solution IMO , ρ(L^2)(v^2) can also be written as ρ(L^4)(T^2) , so Force is proportional to...
  25. kenok1216

    Reduction formula (sinx)^n inequality

    Homework Statement part c Homework Equations The Attempt at a Solution Jm+2=m+2-1/m+2 Jm=m+1/m+2 Jm hence Jm+2<Jm should i expend Jm+2 Jm+1 Jm to the term J0 then compare them? why the inequality is <= but not <? should i use M.I to proof it??[/B]
  26. H

    Automotive What is the formula for force in an engine?

    hi. i want to know how much force acts on every piston in an v8 engine and how much torque acts on the crankshaft . pls also tell me how much energy is created in an engine and how much of it is lost, say in friction and other factors. pls tell the force at start of engine in car and at...
  27. wrobel

    Rare Kinematic Formula - Comments

    wrobel submitted a new PF Insights post Rare Kinematic Formula Continue reading the Original PF Insights Post.
  28. Daringpear

    Formula for determining the heat dissipation of a radiator

    Are there any equations out there which can calculate the heat dissipation of a water-cooled radiator with a fan on it? I would assume some of the variables would include: -Volume of the radiator (240 x 199 x 45mm)=2149200mm^3 -Specific heat of water (4.187 kJ/kgK) -Specific heat of the copper...
  29. S

    MHB Formula Using Retention Rate - Am I thinking this through correctly?

    I need help making sure I am doing this right... I am trying to solve for the total Lifetime Value of a member where I deduct their initial order from the total. Variables: A = # of members B = 42% retention rate C = \$750 lifetime spend D = \$48 initial order Total Lifetime Value = ABC -...
  30. N

    A formula for conservation of energy

    for my physics class a was working on a formula about conservation of energy could you guys tell me if it is somewhat right and stuff i forgot about =constant/s so this is my try making a formula about the total energy in the universe
  31. J

    How can the 0.5 in the acceleration and distance formula be explained?

    Hello all, First of all I want to let you know that my question is very basic and that it involves discrete changes in velocity due to acceleration for every given Δt. I was trying to derive the relationship between the distance and acceleration in a formula and here's what I came up with: 1...
  32. avito009

    I Explain the formula, rpm unit conversion

    Revolutions(RPM) * Pi/30 = Angular velocity What is the purpose of pi/30 in the equation. Why can we not just use rpm as unit of measure of angular velocity?
  33. M

    I Problem in Deriving Rayleigh-Jeans Formula

    Hi I am having trouble with the derivation of the Rayleigh-Jeans from the steps shown at the hyperphysics web site. I have emailed Dr. Rod Nave who is listed as the person-in-charge at the site but I have been able to get a reply. It would really be much appreciated if anyone can have a look at...
  34. M

    Some simple heat transfer formula derivations and questions

    Hi. I would like to ask a simple question. Here is the link of the file I study on. Immediately before the formula 4.9 for Biot number. Lc=V/As but I cannot understand it and I think it is not clear enough. How it appears, for what the word "characteristic" stands for, for example a pipe? For...
  35. DaTario

    I Euler's Formula for planar graphs - 1 or 2 ?

    Hi All, Regarding the Euler's formula Vertices - Edges + Faces = constant, for planar graphs what is the most frequent number? 1 or 2? I understand that it is 2 when the outer region is included in the count. Best wishes, DaTario
  36. W

    Calculating Resistance in Prototype Boat using Formula of Force

    Homework Statement A model boat 1/100 size of its prototype has 0.12N of resistance when stimulating a speed of 5m/s of the prototype , what is the corresponding resistance in the prototype ? water is the fluid in both cases and frictional forces can be neglected. Why the author need to...
  37. A

    How to properly rearrange formula

    I tried rearranging the formula multiple times but the answers I got made no sense. The equation I have to use is a=(v2-v1)/t I need to solve for v2 v1=1 a=2.27 t=3.88 If you cold help me rearrange the formula correctly that'd be great! Thanks!
  38. I

    B Need a formula for this scenario....

    So I've been wondering if anyone knows a formula to relate these quantities in this scenario. Say I have a container that originally has some volume, some amount of atoms at a constant velocity and is at a certain pressure and is airtight and then connect it to another container that has twice...
  39. ShayanJ

    Derivation of rotation formula in a general coordinate system

    Homework Statement [/B] In a set of axes where the z axis is the axis of rotation of a finite rotation, the rotation matrix is given by ## \left[ \begin{array}{lcr} &\cos\phi \ \ \ &\sin\phi \ \ \ &0 \\ & -\sin\phi \ \ \ &\cos\phi \ \ \ &0 \\ &0 \ \ \ &0 \ \ \ &1 \end{array} \right]##...
  40. A

    What Is the Difference Between PV = nRT and Pv = RT?

    There are two formula as below: 1. PV = nRT 2. Pv = RT (v is specific volume) What is the difference between them?
  41. StarWarsNerd

    What is the correct collision formula in this scenario?

    I am working on a simple space game, and I am having trouble figuring out how to do collisions correctly; things bounce in the wrong direction or just get stuck together. Here are the things that are given: Direction of objects A + B in degrees Speed of objects A + B in meters per second Mass...
  42. A

    Output pressure formula for a pressurized waterjet

    Hello, We have a pressurized Water-jet stream, where the nozzle d= 0.8 mm. We can measure the fluid output in mm3/s, to determine the speed by dividing over the area. For this, F=ρAv2 However, the variable that would be changing, would be the distance from the nozzle to the target. If we...
  43. RobertColman

    How can I derive a formula for change in B field strength?

    I'm a bit stuck on this question (which is homework so hints are more welcome than outright answers). The question is: A very long wire carrying a current I is moving with speed v towards a small circular wire loop of radius r. The long wire is in the plane of the loop and is too long to be...
  44. Y

    Formula Debate: Is P=V*I Different Than P=I*V?

    Hello all, I have a question, probably a controversial one: is there any difference between the Formula- P= V*I and P= I*V? is there any technical difference between the two expressions? thank you.
  45. a1call

    A Can you help me understand the beautiful formula for multifactorials?

    Hi, Can someone please decipher the following "beautiful" formula for me? http://mathworld.wolfram.com/ReciprocalMultifactorialConstant.htmlm(19)=1/19!+?+?+... * What is the next/previous addend in the series sum? Thanks in advance.
  46. prashant singh

    I Section formula, external ratio

    I want to know how mathematician got the idea of external division , how they can say that a point can divide a line externally, what's the reason behind this discovery . Why they discovered it.
  47. W

    Finding the Angle of a Bar PQ using Geometry and Theta

    Homework Statement Homework Equations I want to say I should be using this one: aA = aB + α x rA/B + ω x (ω x rA/B) The Attempt at a Solution The only problem is that if I'm supposed to find the angular acceleration then i'd have to take the... inverse of the cross product? To get it back...
  48. W

    Using Cauchy's integral formula to evaluate integrals

    Homework Statement Use Cauchy’s integral formula to evaluate the integral along γ(t) of (z/(z+9)^2)dz where γ(t) = 2i + 4e^it , 0 ≤ t ≤ 2π. Homework Equations Cauchy's integral formula The Attempt at a Solution I was just wondering is the integral not just zero by Cauchy's theorem since...
  49. Dennis Plews

    B An odd integer series formula?

    A few months ago I posted a simple equation that shows an interesting nexus between the difference between the squares of successive integers and the sums of their roots, viz: Where y = x+1 then (x + y) = (y2 - x2) Recently I expanded this relationship as follows: Where n is any integer and y...
  50. Z

    Formula relating thickness of pipe to fundamental frequency

    Homework Statement I understand how to find the resonant frequency of a closed pipe but when the thickness of the walls varies, the resonant frequency varies. Is there a formula that i can use to find the resonant frequency of a closed pipe given the length, temperature, speed of sound and...
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