What is Loss: Definition and 841 Discussions

Loess (US: , UK: ; from German Löss [lœs]) is a clastic, predominantly silt-sized sediment that is formed by the accumulation of wind-blown dust. Ten percent of the Earth's land area is covered by loess or similar deposits.Loess is an aeolian (windborne) sediment being an accumulation of: twenty percent or less clay and the balance mainly equal parts sand and silt typically from 20 to 50 micrometers per particle often loosely cemented by calcium carbonate. It is usually homogeneous and highly porous and is traversed by vertical capillaries that permit the sediment to fracture and form vertical bluffs.

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  1. J

    B What is the formula for gravity loss on a rocket launch and how was it derived?

    Hello all! Lately i have been looking at many rocket equations, and i was wondering about the gravity loss on a rocket launch. I found the formula for the gravity loss where g is of course the gravitational acceleration, and y is the flight path angle, but can somone explane why it looks like...
  2. F

    Transformer Core Loss Lissajous

    Homework Statement [/B] A single phase transformer circuit is assembled with an RC load. A voltmeter is connected to across the capacitor and an ammeter in series with the primary. The output of the ammeter is connected to the X-channel of an oscilloscope and the output of the voltmeter is...
  3. D

    Extreme Fiber Coupled Laser Diode Power Loss

    What could cause a laser source with fiber coupled laser diodes to have extreme loss of power? The laser diodes have a wavelength of 658nm and have an output rated at 60mW but it seems as though the optical channels actually output ranges between 58 to 70mW. During some troubleshooting I...
  4. Cocoleia

    Loss of kinetic energy due to heat

    Homework Statement I have a bloc sitting on a horizontal table, and we shoot a ball through it. The speed right before entering the block is v and the speed when it exits the block is v/2. I need to prove that the fraction of the initial energy that is lost due to heat is 3/4 - γ/4, where γ is...
  5. H

    Iron loss curve estimation

    Hi all, I am recently calculating the iron loss in a permanent magnet synchronous machine with a speed of 24000 rpm (electrical frequency 800 Hz). However, the iron loss data from the data sheet is not sufficient since only frequency of 50 Hz, 100 Hz, 200 Hz, 400 Hz, 1000 Hz and 2500 Hz are...
  6. F

    Trivial Question - rate of heat loss from hot drink

    Hello people of PhysicsForum Apologies in advance if my prefix selection is inaccurate and for my absolute physics noobness. I know no physics jargon so I'm sure my question will be phrased in the same way a 10 year old might. So here is my silly, trivial question: First of all, remove all...
  7. victorhugo

    Why is power loss = I^2R instead of P=VI or P=I^2R?

    [Moderator note: Thread moved from technical section hence no template. Question text from later in the thread added to this post to make things clear] "A power station generates electric power at 120kW. It sends this power to a town 10 km away through transmission lines that have a total...
  8. moenste

    Power loss in the transmission system with a transformer

    Homework Statement A farmer installs a private hydroelectric generator to provide power for equipment rated at 120 kW 240 V AC. The generator is connected to the equipment by two conductors which have a total resistance of 0.20 Ω. The system is shown schematically in Fig. 1. (a) The...
  9. C

    How does the energy loss change when blobbing on concrete instead of water?

    Homework Statement Blobbing is one of the extreme attractions in aquaparks. A person is lying on a big raft positioned on the surface of water and filled with low-pressured air. Another person jumps down from a given height onto the opposite end of that raft, throwing the lying person in the...
  10. M

    I Probability of one-photon loss from a cavity

    Why is the probability of one-photon loss from a cavity in the time interval ##[t, t+\delta t]## is: ##\kappa \delta t\langle \psi(t)| \hat{a}^{\dagger}\hat{a} |\psi(t)\rangle## where ##\kappa## is the decay rate. It looks like the Fermi Golden rule but it's not exactly it.
  11. J

    Calculate Conduction Power Loss

    Homework Statement Homework Equations power loss = I2R power loss = V2/R The Attempt at a Solution voltage across diode is 0.7V, current is 100A. resistance = 0.01 ohm. Power loss is I2R - 100 * 100 * 0.01 = 100 W Power loss across IGBT = V2/R. V across IGBT = V across Diode = 0.7. R for...
  12. EnumaElish

    Can there be insurance for data loss due to EMP

    If an insurer were to offer a policy against data loss from a catastrophic event such as an electromagnetic pulse, the insurer would be in no position to pay when the contingency occurs, the reason being that all of his own bank account will have been wiped clean by the same EMP. Therefore I...
  13. W

    Bernoulli equation exercise from Fanning and Moody

    Homework Statement I would really appreciate it if you could give me a hand with this exercise, not sure on what I've done. Data: Moody: L=55*10-3m D=10-1m k=0.0002m Homework Equations ##Re=\frac{D*u*ρ} {μ}## ##Re=\frac{4*m} {pi*D*μ}## Relative roughness ##ξ=\frac k D## where k=rougness...
  14. I

    Energy Loss in Plastic Scintillator

    Homework Statement Calculate the energy loss loss ##\Delta T## for protons, deuterons and ##\alpha##-particles between ##10## to ##200##MeV when they're passing through a 2mm thick plastic scintillator. Suppose ##Z/A=0.56##, ##I=65eV## and ##\rho = 1.10##g/cm^3. Homework Equations Bethe...
  15. D

    Regarding a MOSFET's reverse recovery power loss

    Hello everyone, so I'm currently trying to find out how much power will be lost during reverse recovery of a MOSFET's diode. I'm using this paper for reference, https://www.fairchildsemi.com/application-notes/AN/AN-6005.pdf the equation they end up with is P= Qrr*Vin*Freq_sw the problem is...
  16. H

    Loss of GPE of a linearly growing raindrop

    Consider a spherical raindrop that falls at a constant velocity and whose radius ##r## is proportional to the distance ##h## fallen, i.e., ##r=kh##. Find the loss of gravitational potential energy (GPE) after it has fallen a distance ##h##. The given answer is ##mg\frac{h}{4}## but my answer is...
  17. S

    B Carbon-14 to Nitrogen-14 Decay: Proton Gain & No Electron Loss

    How Carbon-14 effectively gains a proton but no electrons when decaying to Nitrogen-14...?
  18. B

    AC Alternator Load Loss on Engine Performance

    I'm trying to determine the amount of load (power loss) a theoretical engine will suffer from an AC alternator, such as one you would find on an automobile engine, they produce something of 40 amps with 110 volts I believe? To be specific, I'm curious to know how much a theoretical engine would...
  19. Buggsy GC

    Why does AC have less copper loss than DC

    Hi there everyone, I'm doing some study on electronics and the section on the advantages of A/C over DC mentioned that AC has less copper loss (I^2 x R), But to me this seems contradictory to the skin effect. Could someone please tell me why AC has less copper loss.
  20. M

    Some questions on pressure drops and head loss in pipe flow

    I would like to ask you that why pressure drop is constant through pipe? How can we know that dP/dx=constant? Thank you.
  21. TiernanW

    Calculating the loss of Potential Energy of water in turbine

    Homework Statement Homework Equations Power = Work Done / Time Work Done = Force * Displacement PE = mass * gravity * height The Attempt at a Solution I got the first part (i) right, so the mass of the sea water is 1.32 x 10^12 kg. Part (ii) is the bit I am stuck on. My thoughts were that...
  22. I

    What is the K value for a pipe transition between two different diameters?

    Homework Statement Homework Equations N/A The Attempt at a Solution Usually we are given a table, but how do we calculate the loss coefficient between 2 different pipes with different diameters? In this case, between the 5 and the 3 cm^2 pipes?
  23. I

    If we lose our hearing, are afferent nerves still firing?

    If we lost our hearing from a loud sound, does that just mess up the mechanics of the ear or does it affect the afferent nerves that would actually carry the signal if it could be detected? Thanks for any responses!
  24. N

    Sound Wave Energy Loss due to thickness of aluminum

    Hello everyone! I previously opened a thread asking about sound wave energy loss in aluminum discs based on thickness. I am looking to find out more about exactly how much using a disc that is twice the thickness of the other, (one is 1/8" and the other is 1/4") sound energy would be lost using...
  25. F

    Understanding the Formulas for Major Head Loss in Pipes

    Homework Statement why the author use major loss due to fluid friction is fL(Q^2) / 3(d^5) ? according to darcy weisbech , the major loss due to friction has the formula of fL(v^2) / 2gD why the author wrote it as fL(Q^2) / 3(d^5) ? I don't understand Homework EquationsThe Attempt at a...
  26. F

    Why is the Darcy friction factor used in mechanical engineering calculations?

    Homework Statement the major loss in the fluid due to pipe friction is f(L)(v^2) / 2gD , (darcy weisbech equation) why the author use 4fL(V^2) / 2gD ? in the equation ? is it wrong ? Homework EquationsThe Attempt at a Solution
  27. MoZeeba

    Internal energy loss and momentum conservation question

    A uranium-238 atom can break up into a thorium-234 atom and a particle called an alpha particle, α-4. The numbers indicate the inertias of the atoms and the alpha particle in atomic mass units (1 amu = 1.66 × 10−27 kg). When an uranium atom initially at rest breaks up, the thorium atom is...
  28. N

    Sound Wave Energy loss question

    Hello everyone! I am currently working on a project where I have a piezoelectric sound transducer connected to a glass tube via an aluminum disc. I got two aluminum discs with one twice the thickness as the other. I wanted to know which aluminum disc would work best, the thin one or the thick...
  29. F

    How does pipe thickness affect head loss at entrance?

    Homework Statement I was told that for loss of head at entrance , the degree of contaction depends on how thick the pipe walls is . i really don't know the meaning , can someone clarify ? the author also stated that the loss coefficients will vary , for very thin tubes , k is very high ? head...
  30. C

    Pressure Loss in Parallel Pipes

    Hi, I know this is simple but I'd like someone to clarify for me, because my lecturer wasn't clear: Obviously when the pipes are in parallel, the head losses across them are the same. But what about the total head loss for the parallel pipes as a whole? I have 3 ideas, but I'm not sure which...
  31. Titan97

    Loss in energy of a ball dropped in a fluid

    Homework Statement Two identical balls A and B are dropped from rest into a tall column of viscous liquid. Ball A is dropped from the surface of the liquid while ball B is dropped from a small height ##h## above the liquid. Let ##E_A## and ##E_B## be the loss in mechanical energy of bal A and B...
  32. F

    Friction loss due to exit pipe to reservoir

    Homework Statement we know that the formula of head loss is k(V^2) /2g , the k = 1 when the water is discharged from pipe to reservoir ...However , how if the water from pipe is released into atmosphere ? is it necessary to include the head loss due to exit ? if so , is the k still =1 ? in the...
  33. F

    What is the Formula for Minor Loss Due to Expansion?

    Homework Statement from the previous thread , https://www.physicsforums.com/threads/minor-loss-in-pipe.869148/ , i know that formula of loss due to contraction can also be expressed as k[( mean velocity )^ 2 ] / 2g how about the formula of minor loss due to expansion , can we expressed as...
  34. R

    B Black Holes, Information Loss and Causality Query

    I take an interest in physics in my spare time (in IT during the day). I have a query regarding the 'problem' of information loss at a black hole, and would be grateful for some enlightenment. It seems generally regarded that any information going past the horizon of a black hole is...
  35. F

    Calculating Major Head Loss Due to Pipe Friction

    1. The problem statement, all variables and given/known i am having problem of finding the major loss caused by pipe friction in this question. the formula of major loss is given by fL(V^2) / 2gD , how to get the total length of pipe so that i can gt the major head loss? . Relevant equationsThe...
  36. F

    Minor Loss in Pipe: Which Formula?

    Homework Statement which formula is correct ? the formula in the first ? or in the second ? one is using the mean velocity , while the another one is using velocity difference between vena contarcta and velocity at exit ... Homework EquationsThe Attempt at a Solution
  37. F

    What Does Number of Diameters Mean in Pipe Flow Analysis?

    Homework Statement what is the meaning of number of diameter N ? why the author make L = ND ? and then divide it by D ? Homework EquationsThe Attempt at a Solution
  38. F

    Minor loss due to sudden expansion

    Homework Statement why the minor loss due to sudden expansion is given by formula of [( v_c - v_2) ^2 ]/ 2g ? Homework EquationsThe Attempt at a Solution can it be [( v_2 - v_1) ^2 ]/ 2g ?
  39. G

    Calculate head loss per meter clarification

    Calculate the head loss per metre length of a capillary tube which has a bore radius of 0.45 mm when a fluid of density 850 kg/m3 and viscosity of 25 cP is flowing at a rate of 50 l/hr. State whether the flow is turbulent or laminar. I have attached my attempt at a solution using poiseuille's...
  40. D

    Velocity / Speed loss by shifting to a larger radius

    If there was a free-spinning effective weight of 20 lbs. at a 20" radius rotating at 180 rpm (15.7 fps?) and a force of 20 foot pounds was added, what would be the increase in velocity/speed? (Ignoring friction and wind losses).
  41. R

    Fluids: Energy equation involving head loss

    Homework Statement See attached image: Homework Equations p/ρg + V^2/2g + z = constant head loss (major) = f * l/D * V^2/2gThe Attempt at a Solution To use the energy equation while incorporating head loss, I need to determine the velocity in each section of pipe. The problem is I don't know...
  42. F

    How to calculate head loss in a pipe with sudden diameter expansion?

    Homework Statement estimate the energy head lost along a short length of pipe suddenly enlarging a diameter of 350mm to 700mm which discharges 0.7(m^-3) of water per second . the solution given is Q1= Q2 = 0.7(m^3)/s 0.7 = pi ((350x10^-3)^2 ) V1 / 4 , V1= 7.28m/s 0.7 = pi ((700x10^-3)^2 ) V2 /...
  43. F

    How Do You Calculate Head Loss in a Venturi Meter Using Bernoulli's Equation?

    Homework Statement A venturi meter is being calibrated horizontally and has a diameter of 75mm at the entrance and 50mm at the throat . The flow rate is obtained by measuring the time required to collect certain amount of water . The average number of measurement gives 0.614m^3 of water in...
  44. T

    Specific iron loss of transformer

    I am designing 3ph distribution transformer. So for calculations regarding to design, I want specific iron loss. I know how to find out iron loss but that requires initially specific iron loss of material, which i don't know how to calculate. I also searched it on google and in some books but...
  45. S

    Fresnel Loss & Brewster's Angle

    Homework Statement I'm trying to understand these two a bit better in terms of lasers. Fresnel Loss - The loss that occurs when there is a change in refractive index. Some light will be transmitted, while other light will be reflected back into the medium. This is bad for lasers because it...
  46. M

    Head Loss and Pressure Rise During Gradual Expansion

    Homework Statement , There is an Head Loss question, two pipes join and expanding parts 30 degrees from the horizantal. Homework Equations The Attempt at a Solution Before attemting a solution I try to understand what a1=a2=1.06 is? Would you like to give some information about it...
  47. F

    Formula of friction loss due to expansion

    Homework Statement in the first picture , K_L = [ [(1/C) -1] ^2 ] taking the diagram in the first picture as an example , the K_l = [(1- (Asmall/ Abig)) ^2 ] , the A small represent the area at A2 , Abig = A1 ? Am i right ? Homework EquationsThe Attempt at a Solution
  48. P

    Momentum and percent kinetic energy loss

    Homework Statement 1.) A 1200 kg car traveling at 20 m/s collides with a stationary 1400 kg car. The two cars lock together. Determine the speed of the vehicles immediately after the collision if 80% of the initial kinetic energy is converted to heat and sound during the collision 2.) Must all...
  49. F

    Friction loss is significant in short pipe

    Homework Statement i was told that the friction loss is significant in short pipe , but not so significant in long pipe . However , the friction formula is given by formula f(L/D)(V^2)/2g , as L is big , friction loss is big . so the friction loss is big , right ? Homework EquationsThe...
  50. F

    Loss of head at submerged discharge

    Homework Statement in the notes , author said that the velocity within it is negligible? does the author mean the water velocity in the tank ? so the velocity (v^2)/2g in the 4.24 means the velocity in the pipe ? Homework EquationsThe Attempt at a Solution
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