What is Average: Definition and 1000 Discussions

In colloquial language, an average is a single number taken as representative of a non-empty list of numbers. Different concepts of average are used in different contexts. Often "average" refers to the arithmetic mean, the sum of the numbers divided by how many numbers are being averaged. In statistics, mean, median, and mode are all known as measures of central tendency, and in colloquial usage any of these might be called an average value.

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  1. mihailo

    Average velocity of free particle

    Homework Statement The wave function is given as Ψ(x,t) = Ae^[i(k1x-ω1t)] + Ae^[i(k2x-ω2t)]. Show that particle average velocity Vav = ħ(k1+k2)/2m equals ω2-ω1/k2-k1. Average momentum of the particle is Pav = ħ(k2+k1)/2. Homework Equations p = ħk E=ħω K = 1/2 * mV^2 The Attempt at a Solution...
  2. dyavol33

    Calculating Average Speed: Physics Homework Problem

    Homework Statement So here's a problem I need help with for my physics class that's due tomorrow night. On a road trip, a driver achieved an average speed of 76 km/h for the first 86.0 km and an average speed of 38 km/h for the remaining 54.0 km. What was her average speed (in km/h) for the...
  3. D

    A Change in average atomic mass in universe through time?

    My understanding is that matter tends to converge and form stars and in those stars fusion creates heavier atoms from lighter atoms, and this process repeats continuously. if this is true wouldn't it imply that throughout these star cycles the average atomic mass will just increase, and as the...
  4. F

    Floating, hydrostatic forces, average density

    Hello Forum, I am revisiting Archimedes principle and its important consequences. I am aware that a cube (homogeneous) made of iron will always sink in water regardless of its mass. If we changed the iron cube into a different shape (cone, cylinder, prism, parallelepiped, etc.), the object...
  5. Twigg

    I Effect of a Moving Average on Gaussian Noise

    Hi all, I think there is a really obvious answer to this, but I just don't see it yet. Suppose you had N data sets that all measured the same quantity as a function of time. Each data set shows the same signal plus a random noise component which is normally distributed about the signal with a...
  6. S

    Measuring Pulsing Current Output Average From Photodiode

    Hello all, I will be using a photodiode to measure optical power. The photodiode will convert this power into a current. The optical power will pulse rapidly in 15 ns periods with a 5 ns on-time (at full amplitude) and a 1 ns rise and fall time. I am looking for an analog averaging solution...
  7. cpscdave

    I What is the average time to do a pass when data is read after a period of time?

    Hi there, I'm trying to model how much faster we will be able to pull data from a set of controllers. I know how long it takes to read a single data point from each controller. Right now we are reading each and every data point. The change I would like to model is some of the data isn't read...
  8. KitsonSteam22

    How do you calculate the average force on a piston?

    1. How do you calculate the average force on a piston in one stroke from TDC to BDC given the following Kg forces and their distances in mm from TDC? 1 mm 2 mm 3 mm 4 mm 5 mm 6 mm 7 mm 8 mm 9 mm 10 mm 12 mm 13 mm 9.9 Kg 7.8 Kg 6.3 Kg 5.3 Kg 4.4 Kg 3.8 Kg 3.2...
  9. jk22

    I Skewness and recomputing the average

    Suppose i have a non null skewness. Then this means in some sense that the average computed is not a good measure of average ? How could i recompute an average out of skewness so that it becomes zero and which skewness measure should i take ?
  10. C

    Calculating average velocity for this kind of motion

    Homework Statement For the first half of a straightly traveled path which is α=60° from some reference line, a body is moving with a velocity of v1=72 km/h. During the second half of a straightly traveled path, the body is moving with an angle of β=30° with a velocity of v2=36 km/h.What is the...
  11. S

    MHB Solving a Program to Take & Average Unknown Number of User Inputs

    I want to alter my program so it can take an unknown amount of elements (user inputs). I want the program to automatically count the numbers the user is inputting up until they hit enter to the next line. I think I got the program to keep track of this but now my output is a bunch of zeros in...
  12. alaa amed

    Average rate of change of the area of the triangle?

    Homework Statement An object is moving around the unit circle with parametric equations x(t)=cos(t), y(t)=sin(t), so it's location at time t is P(t)=(cos(t),sin(t)) . Assume 0 < t < π/2. At a given time t, the tangent line to the unit circle at the position P(t) will determine a right triangle...
  13. S

    Average Kinetic Energy of Gas

    Homework Statement Calculate the kinetic energy of CO, CO2, and SO3 at 276 K . Homework Equations KE = (3/2) RT KE= (1/2)(mass)(velocity)^2 The Attempt at a Solution [/B] For CO: First attempt: KE=(3/2)(RT)=(3/2)(8.314 J/mol-K)(276K) = 3441.996 -- So that's wrong Second attempt: Relative...
  14. X

    Help solving for average force please

    Homework Statement When it crashes into a bridge support that does not move, a car goes from 85 km/h to 0 in 1.23 m. A) What is the impulse delivered to the 70-kg driver by the seat belt, assuming the belt makes the driver's motion identical to the car's motion? Assume that the initial...
  15. Z

    What Is the Average Reading Rate for Beth's Day?

    In the afternoon, Beth read 100 pages at the rate of 60 pages per hour; in the evening, when she was tired , she read another 100 pages at the rate of 40 pages per hour. What was her avg rate of reading for the day? I can't understand why are we not finding avg time? Homework Equations S= v *...
  16. Q

    How to calculate average velocity given distance and time?

    Homework Statement A motorist drives north for 35.9min at 73.3km/hr and then stops for 15.4min. He then continues north, traveling 114.5km in 1.93hr. What is his average velocity? Homework Equations avg velocity = xf - xi / time The Attempt at a Solution 35.9 min * (1 hr / 60 min) = 0.5983...
  17. A

    Testing Is it possible to get 90% average in your final year exams?

    Hi guys, new member here. I am entering my final year of university and really want to give it my best shot. Have people on here or anywhere else ever got 90% or above average in their module marks for final year? My final year involves optics, solid state physics, statistical mechanics...
  18. JiJiasd

    What is the average power of a boy

    Homework Statement A boy trample everything he can on his tricycle and manages to briefly hold speed 9 km / h on flat ground. When he stops pedaling cycle continues by itself 7.5m bout it stops due to friction. The boy and the bike weighs together 21 kg. How large average power develops boy...
  19. M

    Heat and mass transfer analogy to find average Nusselt no.

    I am trying to find an expression for the average Nusselt number corresponding to heat transfer from an isothermal disk. Given: ShD≡hm(r)D/DAB=Sho[1 + a (r/ro)n] (1) Sho=hm(r=0)D/DAB=0.814ReD1/2Sc0.36 (2) Relevant equations: Average nusselt number is defined as Nuav=havD/k where k...
  20. ThePizzaDeliveryGuy

    Average Passenger Plane Terminal velocity with added speed

    A passenger plane is traveling at a speed of 500 knots, has a mass of 72574.7792 kg, and has an altitude of 35,000 feet. If the pilot lost control of the plane and couldn't reduce speed or anything and the plane was going down at approximately a 40 degree angle, how long would you have until it...
  21. Parsifal1

    Calculating Average Pressure for Tank Thrust

    I need to work out average pressure in order to work out horizontal thrust on an oil tank. I know that pressure=density*height*acceleration, although I want to know what 'top' and 'bottom' surfaces refer to. There is a tank filled with liquid, to a given depth and the height of the tank is...
  22. physea

    How to calculate average stress?

    hello! In the question below, is the average normal force in order to calculate the average normal stress, 8sin60 or 16sin60 or 0? https://www.physicsforums.com/attachments/stress-jpg.100364/ thanks!
  23. L

    Car acceleration kinematics give average power

    Homework Statement The performance of a car is being tested. Distance driven is 400m. The car accelerates from a standing start (v0 = 0). (reader's note: It could be plausibly assumed that car performance tests are measured at even ground.) The car's mass is 1150kg. The time taken in the...
  24. I

    Finding average current through resistors R1 and R2

    Homework Statement Find the average currents through resistors R1 and R2 Homework EquationsThe Attempt at a Solution I have a question , how do I analyse this circuit besides solving differential equations using laplace transform which takes too much time, what is really confusing me is the...
  25. R

    Average Velocity from Velocity Profile

    Hi I have velocity profiles at different lateral position of a channel. I want to calculate average velocity from velocity profile at those position. Can you suggest me any equation or literature? I attached here a sample datasheet also.
  26. B

    I Calculating average density of the Universe

    Q: What was the average density of the universe at the time the light was emitted by the z = 6.56 galaxy? For the question we know the current average density of the universe and red-shift wavelength z = 6.56. It says to calculate the average density of the universe at the moment when light was...
  27. ecoo

    B True unit of average integral result

    For example, when you have a function that describes the amount of water (liters) in a cup relative to time (the amount fluctuates for whatever reason). If you wanted to find the average amount of water in the cup in the interval [a,b], you would take the integral of the function in that...
  28. P

    A question about Rectilinear motion

    Homework Statement Q: If a particle moving along a straight line under uniform acceleration covers successive equal distances ( S each) in time intervals t1, t2 and t3 respectively, then the expression for average speed of particle in covering the given distance of 3S is: Options: A) (S/t1)...
  29. Mr Davis 97

    Is My Average Value Calculation for Function g(x) on Interval [-π, 0] Correct?

    Homework Statement The average value of the function ##g(x) = 3^{\cos x}## on the closed interval ##[- \pi, 0]## is: Homework Equations3. The attempt at the solution I used the standard method for finding average value over an interval with my calculator using an integral, and got the answer...
  30. J

    Average Speed Calculation: Why 2x266.67 Doesn't Work

    1. Homework Statement Ok so for part ii) b) I calculated the average speed as follow, Average speed= 3792.6/ (2x266.67), where 3792.6m is the total distance, and 266.67s is the time when v=0 , i.e. the time from O to the turning point But it should be 3792.6/ 400, where 400s is the time...
  31. onemic

    Average Speed With Ambiguous Distance/Time

    Homework Statement A locomotive travels on a straight track at a constant speed of 40 mi/h, then reverses direction and returns to its starting point, traveling at a constant speed of 60 mi/h. What is the average speed for the round-trip? Homework Equations avgS = distance/time t = d/40 The...
  32. L

    How Should Uncertainty Be Handled When Averaging Measurements?

    Homework Statement This isn't a specific problem. It's more of something that I have encountered before and I have been unable to find an answer to by looking online or through notes. Hopefully this thread might serve others with similar problems in the future. Say for example, you want to...
  33. N

    Average Investment: Find Total, Lowest & n

    Homework Statement A large company insists that each shareholder invests at least £12,000 in the company. At present, the company has two thousand shareholders and their average investment is £13,040. How much is their total investment?Suppose that 100 new people become shareholders in the...
  34. S

    Angle of average acceleration while turning a curve

    Homework Statement A cyclist is initially heading exactly due North. He then initiates a turn to the West, the turn being a quarter circle with radius 12-m. He travels at a constant speed of 5.5-m/s during the turn. What is the direction of this average acceleration, measured anti-clockwise...
  35. W

    Finding average velocity in a velocity distribution

    Homework Statement A gas has a hypothetical speed distribution for N gas molecules with N(v) = Cv^2 for 0 < v < V0. Find (i) an expression for C in terms of N and v0 (ii) the average speed of the particles Homework Equations N/A The Attempt at a Solution (i) integrating N(v) with respect to v...
  36. C

    B-field to create average emf in rotating coil

    Homework Statement A 0.300 m radius, 487 turn coil is rotated one-fourth of a revolution in 4.17 ms, originally having its plane perpendicular to a uniform magnetic field. (This is 60 rev/s.) Find the magnetic field strength needed to induce an average emf of 10,000 V.[/B]Homework Equations E...
  37. throneoo

    Average photon energy from a galaxy cluster

    Homework Statement I want to calculate/estimate the average photon energy from a galaxy cluster incident on the mirror of a X ray telescope (Chandra to be specific) . The cluster has redshift z and at constant uniform temperature T Homework Equations Specific Intensity of thermal...
  38. lasisdabomb

    Calculate the Average Surface Temperature of Earth

    Homework Statement The Earth receives on average about 390 W m−2 of radiant thermal energy from the Sun, averaged over the whole of the Earth. It radiates an equal amount back into space, maintaining a thermal equilibrium that keeps the average temperature on Earth the same. Assuming the Earth...
  39. Geek007

    A Average amplitude of signal is zero, why?

    hi there, Why does we need to have a signal which always has the average amplitude of zero. i read some where that it would be inefficient for over transmission medium to carry a signal which have amplitude great than zero. Why?
  40. J

    I Average number of times a random walk passes a point

    Hi, I'm trying to work out how many time a particle going on a random walk starting at the origin would pass a particular point or points for a given total number of steps. I've simulated the problem and get approximately the same answer every time, however I'm struggling to know where to even...
  41. M

    MHB Therefore, Kenny scores 31 points in the last test.

    After the fourth test, Kenny's average mark rises by 5 points, but after the fifth test, it drops by 9 points. If his total score in the last two tests is 122 points, How many points does he score in the last test?
  42. K

    Finding average force and time

    Homework Statement When an 98.0-g piece of toast is inserted into a toaster, the toaster's ejection spring is compressed 7.20 cm. When the toaster ejects the toasted slice, the slice reaches a height of 3.4 cm above it's starting position. What is the average force that the ejection spring...
  43. K

    Average height of molecules in a box as a function of temperature

    Homework Statement A circular cylinder of height H is filled with monatomic gas molecules at temperature T. The cylinder stands on the surface of the Earth so that the gas molecules are subject to the gravitational field g. (a) Find the average height, z , of the molecules in the cylinder as...
  44. I

    Exploring the Physical Application of Calculating Average Value of a Function

    Hey everyone, I am preparing for a Calc 2 lecture tomorrow with KhanAcademy videos. I was watching a video on average value of a function in which he said, basically, you'll have some definite integral on a to b divided by (b-a). My question is, is this essentially calculating average speed? I...
  45. M

    Calculate the average resultant force required to accelerate the ball.

    Homework Statement A 56 g tennis ball is accelerated at 1000 m s-2 to reach its service velocity. Calculate the average resultant force required to accelerate the ball. Homework Equations F = MA The Attempt at a Solution Mass = 0.56g = 0.056kg Acceleration = 1000m/s2 0.056 x 1000 = 56N...
  46. L

    Average of Momentum for 1D Quantum Harmonic Oscillator

    For a 1D QHO we are given have function for ##t=0## and we are asked for expectation and variance of P at some time t. ##|\psi>=(1/\sqrt 2)(|n>+|n+1>)## Where n is an integer So my idea was to use Dirac operators ##\hat a## and ##\hat a^\dagger## and so I get the following solution ##<\hat...
  47. Z

    Stat Mech, question about average of function of ith state.

    I just started learning some Stat. Mech by Leonard Susskind's lectures and am in a part briefly overviewing basic probability in general; One of the things brought up was F(i), some quantity associated with the ith state of a system, and the important average of F(i) averaged over the...
  48. jdawg

    Fluid Mechanics:Volumetric flow rate and average velocity

    Homework Statement . Air, at a flow rate of 30 [N/s], flows through the reducer shown below. In the 300 [mm] diameter section of the pipe the specific weight of the air is 9.8 [N/m3 ]. When flowing through the reducer the pressure and temperature will fall causing the air to expand and...
  49. C

    Multivar; Path length, and average y-value over it

    Homework Statement Letting c(t) =(t2,t,3) for 0<t<1 (Really it's a smaller than or equal to sign) 1. Find the length of the path 2. Find the average y coordinate along the path Homework Equations What we're given in the book: (These equations are not necessarily relevant) (formula 1) l(c)...
  50. Marcin H

    Finding Average Values in a Waveform: Understanding the Concept and Calculation

    Homework Statement Circle all that are correct Homework Equations V(t)=Vocos(wt) The Attempt at a Solution I don't really understand what the question wants when they ask for an average value. Average value of what? And how do you find it. There are a lot of questions with graphs like this...
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