Ratio Definition and 1000 Threads

In mathematics, a ratio indicates how many times one number contains another. For example, if there are eight oranges and six lemons in a bowl of fruit, then the ratio of oranges to lemons is eight to six (that is, 8∶6, which is equivalent to the ratio 4∶3). Similarly, the ratio of lemons to oranges is 6∶8 (or 3∶4) and the ratio of oranges to the total amount of fruit is 8∶14 (or 4∶7).
The numbers in a ratio may be quantities of any kind, such as counts of people or objects, or such as measurements of lengths, weights, time, etc. In most contexts, both numbers are restricted to be positive.
A ratio may be specified either by giving both constituting numbers, written as "a to b" or "a∶b", or by giving just the value of their quotient a/b. Equal quotients correspond to equal ratios.
Consequently, a ratio may be considered as an ordered pair of numbers, a fraction with the first number in the numerator and the second in the denominator, or as the value denoted by this fraction. Ratios of counts, given by (non-zero) natural numbers, are rational numbers, and may sometimes be natural numbers. When two quantities are measured with the same unit, as is often the case, their ratio is a dimensionless number. A quotient of two quantities that are measured with different units is called a rate.

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  1. S

    Fraunhofer Diffraction Pattern Ratio of Power Densities

    Homework Statement Find an approximate expression for the ratio of the power densities at the principal maximum to that at the first secondary maximum on either side, in the Fraunhofer diffraction pattern of an N-slit multiple aperture. Assume that the slits are much narrower than their...
  2. S

    Calculating the Ratio of Apparent Weight on a Ferris Wheel

    Homework Statement A Ferris wheel 26 m in diameter rotates once every 14 s. What is the ratio of a person's apparent weight at the top of the ride to her apparent weight at the bottom of the ride? Homework Equations [/B] FNT/FNB = mg - mv^2 / r / mg + mv^2/r The Attempt at a Solution...
  3. vAhmed

    Calculating a ratio in Free Fall motion

    Homework Statement A ball is thrown upward with a speed v 1. The ball reaches a maximum height of y=h. What is the ratio of the speed of the ball,v 2 , at y=h/2, to the initial upward speed of the ball,v 1 , at y=0? Homework Equations I attached a picture. We are currently studying the four...
  4. N

    A What is the dust-to-gas ratio in oxygen-poor galaxies?

    Hello, Assuming that dust is formed by silicates with Mg and Fe. What is the largest possible silicate dust-to-gas ratio in mass?
  5. G

    Chemistry How to Convert a Number Concentration into Volume Mixing Ratio?

    Homework Statement Convert a number concentration of 15 X 10^12 molecule/cm3 into volume mixing ratio at: a) 1 atm pressure, and 20 C temperature. b) 500 mbar pressure, and 253 K temperature. Using the Ideal Gas Law, calculate: a) Loshmidt’s number (# of molecules/cm3 of air, at standard...
  6. J

    Projectile motion with only distance, an angle and a ratio

    Homework Statement launch angle of θ=41.86°. The distance to the wall is d=11.06 m, and it strikes the wall with speed that is a fraction f=0.925 of the initial speed, while it is still gaining height (i.e., it has not the highest point of the trajectory). What is the initial velocity? Express...
  7. G

    Question involving Slenderness Ratio and E.S.R.

    Homework Statement A column has the dimensions shown in the diagram below. (a) What is the minimum length of the column at which buckling is likely to occur? (b) If the column is the length determined in (a), (i) What will be the mode of failure? (ii) At what load would you expect failure to...
  8. P

    Energy: What will be the minimum ratio of m/M here

    Homework Statement The objects are set free from the scenario shown in the attached image. Their masses have been given and they are under the effect of gravity. The length of the string has been shown in the figure. If the two blocks cross each other, then we need to determine the minimum...
  9. M

    Automotive Max Power Output with Air-Fuel Ratio

    How can the slightly richer Air fuel ratio produce higher power while the temperature it produces is lesser than slightly leaner(slightly leaner than stoichiometric for best economy)? FYI:I understood that ,at the stoichiometric ratio(precisely slightly leaner due to fast operation of engine)...
  10. otaKu

    Confused about the Signal to Noise Ratio

    Hello everyone! It seems to me that there are many ways of calculating SNR depending on the type of signal and the nature of problems. I was able to get a decent amount of information for electrical signals but couldn't find resources which discuss the topic in a more generalized manner. I was...
  11. D

    Ratio of Inductance between 2 Solenoids?

    Homework Statement [/B] 1. Two solenoids, A and B, are wound using equal lengths of the same kind of wire. The length of the axis of each solenoid is large compared with its diameter. The axial length of A is twice as large as that of B, and A has twice as many turns as B. What is the...
  12. M

    Chemistry Why moles of (S2O3 2-) is equal to mol of ( MnO4-) times 5

    Homework Statement The ratio of KMnO4 to I2 is given by 2 MnO4 - + 16 H+ + 10 I - ⇌ 2 Mn2+ + 5 I2 + 8 H2O the ratio is 2:5 - The ratio of I2 to S2O3 2- is given by 1 I2 + 2 S2O32- ⇌ 2 I-+ S4O5 2- the ratio is 1:2 therefore n(S2O3 2- ) = n(MnO4 - ) x 5 Homework Equations Why the mole of...
  13. M

    MHB How to Understand the Ratio of Quadratic Roots?

    86 https://uploads.tapatalk-cdn.com/20180712/7faa109f841501a10a2d07b6e8e10681.jpg
  14. W

    I Ratio of Normal to Dark Matter: Unchanged Since Beginning?

    Has the ratio of normal to dark matter remained the same since the beginning?
  15. W

    I Distribution of ratio std Normal and sqrt chi squared

    Hi all, I am trying to understand two things from a paper The ratio of a standard normal by the square root of a a chi squared divided by its df ( degrees of freedom) is a t distribution. So 1) What is the dist of square root of Chi squared? I know a normal squared is a chi squared, but a chi...
  16. Arman777

    When Does the Prime Ratio of Spiral Diagonals Drop Below 10%?

    Homework Statement https://projecteuler.net/problem=58 Homework EquationsThe Attempt at a Solution def prime(N): if N == 1: return False y = int(N**0.5) for i in range(2,y+1): if N%i == 0: return False return True def finder(N): L = len(N)...
  17. G

    Volume ratio in an adiabatic gas expansion

    Homework Statement Consider a perfect monoatomic gas at pressure $p_i$ 1.2 atm and temperature $T_i$ 300K, that is in equilibrium inside a cylinder having a volume $V_i=1L$ and which piston has a mass of 1kg and is at an height of 50 cm. Admit that a mass M=3.13kg is over the piston. When that...
  18. D

    Finding the CMOS transistor width ratio

    Homework Statement Calculate the ration of ##w_p/w_n## if n and p transistors in CMOS inverter necessary for the least delay time ##t_p## if the circuit is used in a chain of circuits. a) What is ##w_p## in that circuit if you're given : b) Calculate the maximum short circuit current if...
  19. Richie Smash

    Calculate the ratio of new volume to old volume

    Homework Statement A car tyre has initial temperature 23°C and inital pressure 2*105 Pa After heating in the sun, temperature is now 34°C and final pressure is 2.1*105Pa Question asks, Calculate the ratio of new volume to old volume (V1/V2) if the pressure is held constant during the...
  20. L

    MHB Why is Angle C Assumed to be Acute and What is the Value of Sin C in ∆ABC?

    Given that √5 tanA=-2 and CosB=8/17 in ∆ABC State why we may assume that angle C is acute and determine the value of Sin CAttempt made: tanA=-2/√5 CosB=8/17 A is obtuse angle of 138° or reflex angle 318.19° B is an acute angle of61.9° or reflex angle298.1 °.Since it is a right...
  21. R

    Should the H/D Ratio Be Positive or Negative for Increased Neutron Leakage?

    Homework Statement A sphere has a height to diameter ratio of 1.00. The greater the surface area to volume ratio of a shape, the greater the neutron leakage. To increase neutron leakage should H/D be positive or negative? Homework Equations H/D The Attempt at a Solution Positive? Good...
  22. T

    Ratio of amplitudes in a damped oscillator

    Homework Statement Show that the ratio of two successive maxima in the displacement of a damped harmonic oscillator is constant.(Note: The maxima do not occur at the points of contact of the displacement curve with the curve Aeˆ(-yt) where y is supposed to be gamma. 2. Homework Equations The...
  23. Rorshach

    Acoustic pressure ratio vs acoustic impedance ratio

    Homework Statement Hello, I have a problem with a quote from a textbook I am currently reading, and it is not strictly a homework problem. It is a part of the book in which authors explain mechanism of sound amplification in human ear, specifically by resonance in ear canal and mechanical...
  24. MermaidWonders

    MHB Solving for Slit Width-Wavelength Ratio at $\pm90°$ Diffraction Pattern

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  25. L

    MHB Ratio of areas of squares - Challenging problem

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  26. Physiona

    Office Ratio & Probability Question

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  27. Vital

    Understanding the ratio formula

    Homework Statement Hello! Please, help me to understand the mathematical logic behind one of the financial instruments called the "money market yield". Here is the equation: money market yield = [ 360 x r BD ] / [360 - (t x rBD)] where rBD is the band discount rate, and for simplicity we...
  28. Vital

    Geometric mean application in finance ratio question

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  29. K

    Finding the ratio of the volumes of a cube and a sphere

    Homework Statement Homework Equations Volue of a sphere: ##~\displaystyle V=\frac{4}{3}\pi r^3## Area of a sphere: ##~\displaystyle A=4\pi r^2## Minimum/Maximum occurs when the first derivative=0 The Attempt at a Solution The fixed area is k, the edge is a: $$6a+4\pi...
  30. M

    Determining the recycle ratio in a PFR

    Homework Statement For an irreversible first-order liquid-phase reaction (CA,0 = 10 mol/L) conversion is 90% in a plug flow reactor. If two-thirds of the stream leaving the reactor is recycled to the reactor entrance, and if the throughput to the whole reactor-recycle system is kept unchanged...
  31. RabbitWho

    I Odds ratio and percentages.... absolute beginner

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  32. S

    I Uncovering the 10 Classes of Ratios in Greek Mathematics

    In the book 'ZERO THE BIOGRAPHY OF A DANGEROUS IDEA' Charles Seife says, "Because ratios were the key to understanding nature, the Pythagoreans and later Greek Mathematicians spent much of their energy investigating their properties. Eventually, they categorized proportions into 10 different...
  33. YNesterov

    How to find m1 in T = ( m1c1T1 + m2c2T2 ) / ( m1c1 + m2c2 )

    Homework Statement How to find mass of one of the two liquids being mixed if we know all other variables in this formula T = ( m1c1T1 + m2c2T2 ) / ( m1c1 + m2c2 ) ? Homework Equations T = ( m1c1T1 + m2c2T2 ) / ( m1c1 + m2c2 ) The Attempt at a Solution
  34. J

    New time constant to change damping ratio

    Homework Statement Homework Equations Time constant = 1/ξwn The Attempt at a Solution Time constant = 1/ξwn Damping factor = ξwn So T = 1/ξwn If ξwn is reduced by factor of 2, then Time constant must be increased by factor of 2. So Answer is: B Book answer is A How? p.s. I know I'm posting...
  35. S

    Chemistry Why Divide the Moles of K by 2 in Combustion Calculation?

    Homework Statement A sample of K (s) of mass 2.740g undergoes combustion in a constant volume calorimeter at 298.15K . The calorimeter constant is 1849 J/K , and the measured temperature rise in the inner water bath containing 1450 of water is 1.60K Calculate the internal energy of formation...
  36. W

    Ratio of Fields from Different Sheets in Excel Pivot

    Hi All, I want to compute the ratio of two fields A,B from different sheets ( same workbook) , using Pivot ( tho "straight" Excel will do*). I tried using the Wizard, but , in the end, could not find a way of doing it: Any ideas, please? *I scewed big when trying this.
  37. alijan kk

    Solve Ratio Word Problem: A & B in 30 & 40 Days

    Homework Statement A can do a piece of work in 30 days while B can do it in 40 days. In how many days can A and B working together do it ? Homework EquationsThe Attempt at a Solution I just imagined walls and paiting work and try to assign them and i found that it tooks 55 days working...
  38. Pushoam

    Ratio of energy densities of black body radiation

    Homework Statement Homework EquationsThe Attempt at a SolutionThe energy density is given as ## u = \frac { 8 \pi {\nu }^2}{c^3}~ \frac { h \nu} {e^{ \frac { h\nu}{k_B T}} – 1}.## EDIT : I put the constant C. ## \frac { u( 2 \nu) } {u(\nu)} = C \frac { {e^{ \frac { h\nu}{k_B T}} – 1}...
  39. C

    I Calculating signal to noise ratio for deimos data

    I'm currently working with the 1d DEEP2 DEIMOS fits files (see http://deep.ps.uci.edu/deep3/specprimer.html) and am trying to define some exclusion criteria in Python 2.7 for the data based on the noise. What's the best way to quantify the noise in order to do this? Thank you!
  40. Pushoam

    Ratio of K. E. of solid cylinder to shell

    Homework Statement Homework EquationsThe Attempt at a Solution total kinetic energy of a rigid body = rotational kinetic energy of the body around its center of mass + translational kinetic energy of center of mass For solid cylinder, total kinetic energy = ## \frac { [I = \frac 1 2...
  41. EastWindBreaks

    Minimum number of teeth given the gear train ratio?

    Homework Statement Homework EquationsThe Attempt at a Solution for this class, we were not taught with contact ratio equations, nor the pressure angle is given, so for this type of problems, do we just assume that minimum number of teeth on a pinion will be 12? 3 integer factors of 180 can...
  42. Dr Wu

    B Discovering the Correct Rocket Mass Ratio for Beginners

    I'd always thought that to find the mass ratio of a given rocket, one simply had to divide the rocket's wet mass (i.e. fuel and propellant) from its total mass. An example: a rocket's total mass = 2,000 tonnes: its wet mass = 1,000 tonnes. Answer: 2. Is this correct? (I'm pretty sure it isn't...
  43. K

    B Exploring Poisson's Ratio in 3D Rectangles

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  44. W

    Expected value of Poison's ratio for a material

    Hello all Currently struggle with a question from one of my assignments concerning poisons ratio . The notes given to me are vague and before i start trundling through the internet i was wondering if anyone could explain it ?
  45. A

    Ratio of shear stress to normal stress along principle place

    Homework Statement "In a component under multi-axial state of stress, the ratio of shear stress to normal stress along principle places is _____. A) 0.0 B) 0.5 C) 1.0 D) 1.5 E)2.0" Homework Equations σx' = (σx+σy)/2 + ((σx-σy)/2)*cos(2θ) + τxy*sin(2θ) σy' = (σx+σy)/2 - ((σx-σy)/2)*cos(2θ)...
  46. J

    MHB Ratio problem: The ratio of Liquid X to Liquid Y in a mixture is 3 to 7

    The ratio of Liquid X to Liquid Y in a mixture is 3 to 7. If the amount of Liquid Y in a mixture is 161, then the amount of Liquid x in the mixture is equal to?
  47. R

    Ratio of electric field to applied magnetic field

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  48. Anonymous123451234

    Inelastic collision, determine ratio KEf/KEi

    Consider the following extreme cases for a completely inelastic collision. In each case, determine the approximate ratio KEf/KEi. a) A moving train collides with a stationary car. b) A moving car collides with a stationary train. I do not understand this question, I'm not given masses or...
  49. S

    B Electron gyromagnetic ratio & lattice qft

    The electron gyromagnetic ratio of 1.0011596522 is computed using perturbation method and Feynman diagrams that is said to produce a value to better than one part in 10^10, or about three parts in 100 billion. Does the nonperturbative lattice QFT also able to compute it? What is the counterpart...
  50. N

    Is it possible to do this without Poission's ratio?

    this is the problem as our professor gave it to us "A steel alloy bar (modulus of elasticity of 205 GPa) is 20mm in diameter and experiances an elastic deformation by applying a force along its axis (IE pulling it apart perpendicular to the circular cross section). Determine the...
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