Loss Definition and 841 Threads

  1. seonjunyoo

    B I have a question about energy & ignoring friction losses

    If the energy itself ignores loss resistance friction and the energy moves forward, can infinity go far at a constant speed?
  2. Hauzen

    I have a hydrodynamic loss head question

    Hi! I have a loss head question. There is a difficulty in understanding the hydrodynamic loss head concept. Assuming that there is a one-sided tube with incompressibility, visibility, tube friction coefficient and cross-sectional area A.. There is friction in the loss head formula, but is the...
  3. pinball1970

    Did Ryan O'Neil Pass Away on December 8th?

    Died December 8th.
  4. SaschaSIGI

    I What Is the Difference Between Loss and Cost Functions in Quantum Computing?

    Hello, Im currently hearing a module about quantum computing and Im wondering what is the difference of a loss and cost function for variational quantum algortihms? Both functions also can be presented into a loss/cost landscape? Are they the same ? Already a big thank you for all the upcoming...
  5. Shovon00000

    Question about the 2nd law of thermodynamics (heat loss)

    Assume that a closed system of cylindar filled with ideal gas consists of a movable piston.We know from the 1st law dQ=dU +dW. According to the 2nd law mechanical energy can be totally converted into heat energy but heat energy cannot be converted completely into mechanical energy.The question...
  6. S

    Rate of loss of potential energy

    I got answer for (a), which is 0.51 m For (b), loss of potential energy = 35 x 9.81 x 0.51 = 175 J Rate of loss of potential energy = 175 J / 1 s = 175 W But the answer key is 80 W. Where is my mistake? Thanks
  7. Alexey_H

    Heat loss from the temperature difference

    Hello, My house has some heat loss. As an example I know the outside door temperature. How can I calculate the heat loss delta if I reduce the door temperature by 1 degree? I know that there is a formula to calculate a heat loss based on the U-value of a fabric. But I can't get those values...
  8. DarkEnergy890

    The Mystery of Heat Loss: Examining Ice Melting Without Heat Loss

    During the procedure, 30% of heat is lost. So that means that 70% of water+container is contributing to melting the ice, right? And the other 30% contributing melting the ice is down to, well, the "heat being lost to the surroundings" (not sure what this really means). We compute the sum and...
  9. gps57

    How can I convert loss units, dB/mm, to mm^-1

    I am trying to simulate mode loss for a waveguide and the units I get for loss are dB/mm, but I want to convert the units to just mm^-1 so I can the absorption (α) value. I am guessing there is a specific value that I need to either multiply or divide my values with, but I'm just not sure what...
  10. J

    What is the temperature loss along a duct with hot air entering?

    Hello, I am looking for assistance regarding temperature losses along a length of pipe with hot air entering one. I need to know the temperature leaving the other end of the pipe. I have been able to calculate the W/m-K (in theory but stopped a i knew the answer wasnt what i needed) losses but...
  11. A

    What is the Power Loss in a Transformer?

    ##\frac{N_S}{N_P} = \frac{240}{12\times 10^3} = \frac{1}{50}## ##I_S = \frac{N_P}{N_S}I_P = \frac{N_P}{N_S}I_P = 50\times 2 = 100## Amps ##P_{loss} = I_S^2R##, but I don't know how to find R
  12. A

    Voltage Drop in Parallel Receptacle Wiring

    I know how to solve the question but I am a bit confused about why there is a current of 3 A and a voltage of 110 V requirement for the refrigerator but the power plant only supplies 110 V. How can there be a voltage drop on the refrigerator load of 110 V, when there is also a voltage drop on...
  13. O

    I Information loss in black hole, why is it a problem?

    If an observer never falls into a black hole, something it observes that does fall in takes an infinite time to reach the event horizon. If an observer falls into a black hole along with an object, it will not lose information on the falling object, but will lose that from the outside of the...
  14. chwala

    Find the percentage loss in the purchase and sale of bananas

    Ok my approach on this, i let the cost price = ##x##, then it follows that cost price per banana will be given by; ##\frac {x}{10}##=##\frac {x}{12}## ##\frac {x}{10}-\frac {x}{12}##= loss ##x####\left[ \frac {1}{10}-\frac {1}{12}\right]##=loss ##x####\left[ \frac {1}{6}\right]##=loss therefore...
  15. shivajikobardan

    Engineering Characteristics of insurable loss-:

    Large loss-: Book says " The size of loss must be meaningful from the perspective of the insured. Insurance premiums need to cover both the expected cost of losses, plus the cost of issuing and adminstering the policy, adjusting losses and supplying the capital needed to reasonably assure...
  16. C

    Missing factor of 2 pi in dielectric loss?

    Hi. I am sure that this is something to do with it being Friday afternoon...but can anyone explain what I am missing here?
  17. A

    A Calculating the heat loss of an open water tank (aquarium)

    Hi, I have been calculating a series of hypothesis for some aquariums/tanks situations, using heat transfer equations (conduction, convection, radiation, evaporation) Typically we have aquariums that run at higher temperatures than the surroundings in winter and lower temperature than the...
  18. Andreas S-H

    B Calculating Energy Loss of Muon Moving Through a Medium

    Hello everyone. I have just complete an experiment calculating the speed of a muon. I got it to 2.6E8 m/s, however I know that they are created at close to speed of light to be able to get down to Earth's surface in their short lifespan. This speed could not have been its initial speed, as it...
  19. D

    Find the pressure drop and power loss of pipe when elevation changes

    Summary:: I can’t get the correct answers, I think I haven’t fully understand the theory behind them The answers are given in the picture
  20. M

    Engineering Calculating Power Losses in an AC Induction Motor

    Given the AC Induction (asynchronous motor) in 3 phases: Parameter Value Pn (Nominal Power) = Pmechanical (output power at the shaft) 5 kW = 5000W uls (Voltage through the stator line) 220 V fstator (stator frequency) 50 Hz p (Number of pole pairs) 2 LFe (Iron loss) = Lmechanical...
  21. O

    AC power loss in lossy dielectric (capacitor) with DC-bias field

    Hi there, if a dielectric (capacitor) is described with a constant permittivit eps (or C) and loss-tangent DF, how much energy ist lost when charging the capacitor by 1V? For example: C=1, DF=0.1. When charging from 0 to 1V, the lost energy (in J) is ...? When charging from 1V to 2V, the lost...
  22. M

    Calculate vacuum loss by using principles of physics, not physical testing?

    We (company I am interning for) are meeting with various suppliers in efforts to find a new source of vacuum pumps for our brake boosters. We are looking to make a switch to an electrical pump versus the mechanically-driven pump we used previously. One of the issues we are having with this is...
  23. S

    Current and resistance in the power loss of a transformer

    a) Output voltage = 2 x 6 = 12 V Current in R = 12 V / 13.5 kΩ = 8.9 x 10-4 A That is the correct answer based on the solution but I don't understand why when calculating the current in R, the resistance of secondary coil is not considered. I thought it should be like this: Current in R = 12...
  24. P

    B Energy loss in the beam of LHC

    Generally, one would expect the beam to lose its content (energy or particles) if it hits anything before its reaching its target. The whole idea of maintaining (conventional) vacuum using pumps or other means is to minimize that loss. But is it possible that there could be a beam loss purely...
  25. P

    I An Alternative explanation for energy loss due to Eddy currents

    Explanation 1: Eddy currents induced, energy loss due to joule heating. Explanation 2: Eddy currents induced, induced magnetic dipole formed. Energy is lost as work has to be done to overcome the attractive/repulsive force due to the magnet and the induced magnetic dipole from the eddy...
  26. A

    What Causes Loss of Particles in a Magnetic Mirror?

    If I am not mistaken (hopefully) then the highest loss through the mirror ends in a magnetic mirror happens with particles that have a higher parallel component to the field lines than a higher perpendicular (gyro frequency). In a magnetic mirror if we map these properties onto the real physical...
  27. chwala

    Solving this rate of decay problem -- Mass loss calculation

    My interest is on question ##11.ii## only. I think there is a mistake on the markscheme...i just need a second opinion on this...find attached the question and markscheme... markscheme here: it ought to be, ##e^{0.0277t}=1.6797##
  28. Haorong Wu

    I Does decoherence mean the loss of entanglement?

    Hello, there. I am studying a model for decoherence of two entangled photons. The space for the first photon is 2 dimensional, while that for the other one is 6 dimensional. In total, the system will be in a 12 dimensional space. Initially, they are set to one of the Bell states, such as...
  29. T

    COVID Significant Loss of Brain Grey Matter after COVID-19

    https://www.medrxiv.org/content/10.1101/2021.06.11.21258690v1 doi: https://doi.org/10.1101/2021.06.11.21258690 Full PDF (32 pages) at: https://www.medrxiv.org/content/10.1101/2021.06.11.21258690v1.full.pdf
  30. Buckethead

    B Lense-Thirring Effect and Energy Loss

    I was thinking about the Gravity-B probe and the rotation of the satellite due to the Lense-Thirring effect. I was imagining that the satellite, once in orbit, was aligned to a distant star using retro rockets effectively rendering it non-rotating relative to that star. That being said, once...
  31. B

    Nozzle loss coefficient that increases with Reynolds number?

    Hi, I started to think about the drag coefficient of a sphere. At high Reynolds number Cd drops of suddenly when the boundary layer separates. If the Reynolds number is increased further, Cd increases with increasing Re. (I'm thinking about what is referred to as "post critical separated flow")...
  32. G

    Engineering Induction motor no load magnetisation loss

    The study material says under 'Estimation of magnetising losses' :On no-load, the rotor current is very small and the slip almost zero. Therefore, R′2s is very high and virtually no current flows through the branch of the circuit containing R′2s. Consequently, the no-load current is virtually...
  33. A

    Speed for loss of of contact between a dumbbell and a table

    Attempted solution: Consider the instant when the normal force of the lower ball is zero. Conserving energy: $$\frac{mv^2}{2}+mgh_1=\frac{mv_1^2}{2}+\frac{mv_2^2}{2} + mgh_2$$ Applying the resulting torque to the upper ball where the rotation point is the lower ball. $$T=I.a =...
  34. D

    How long does it take to pass out from blood loss and bleed out?

    Hi everyone I'm writing a story in which someone passes out from blood loss before they are found and saved. How long might a rescuer have before the victim dies? I'm guessing there might be a lot of variables here, but I'm just looking for the longest possible realistic delay. Also, if...
  35. Y

    Estimating head loss from pipe slope?

    I am trying to calculate head loss for a sloped pipe. I found this calculation here, which seems to be what I want..or at least a start: https://www.pumpsandsystems.com/pumps/april-2015-calculating-head-loss-pipeline My confusion/skepticism arises from the fact that the equations in the above...
  36. Touuka

    Understanding Energy Loss of 2 Joules in Circuits with Changing Capacitance

    I am given the answer is 2J and I know how to get there with U = q^2/2C. But what I don't understand is that why is the energy not conserved here? How can energy loses just because the capacitance is doubled?
  37. Faris ARSLAN

    Approximate energy loss ratio in mechanical springs

    Hi!.. As known, a certain amount of energy is applied for compressing a mechanical spring. Thus mechanical spring is charged with energy and it stores it as elastic-potential energy. But whole energy, applied for compressing spring, can not be converted into potential energy. The reason is...
  38. M

    Optimizing Air Flow for CO2 and Heat Loss in Vans

    My goal is to determine the ideal amount of air flow, in order to keep CO2 below 1000ppm and to minimize heat loss. I calculated the following based off a similar post in this forum, and I am hoping this can be verified so I know that i am in the right ballpark and going in the right direction...
  39. Adams2020

    I Loss of electron & proton energy due to radiation

    Can you compare the energy loss of electrons and protons due to the radiation they emit? In fact, I want to know which of the two loses more energy when it emits radiation.
  40. Frigus

    How to prevent the loss of anki cards

    I have created almost 6000 anki cards on ankidroid(android) and I get nightmares about loosing them by deletion(of course mistakenly) or due to some 5 year old monster who just wants to delete them for fun. I sync the cards daily and I am unsure if I will be able to get my cards back if they get...
  41. S

    Friction loss in water flowing through a globe valve?

    Imagine water flowing inside this from say left to right. Energy can't be destroyed or created. Pressure can reduce due to the three 90 degree turns. Is the pressure or energy loss due to the heat or deformation or kinetic energy loss of the water to the wall inside? What must be the wall be...
  42. cwill53

    Lagrange Multipliers and Energy Loss Question

    Constraint: ##I=I_{1}+I_{2}## ##P_{diss,R_{1}}=I_{1}^{2}R_{1}##;##P_{diss,R_{2}}=I_{2}^{2}R_{2}## We want to minimize ##P_{diss,TOT}=I_{1}^{2}R_{1}+I_{2}^{2}R_{2}## $$f(I_{1},I_{2})=I_{1}^{2}R_{1}+I_{2}^{2}R_{2};g(I_{1},I_{2})=I_{1}+I_{2}=I(constraint)$$ $$\nabla f= \left \langle \frac{\partial...
  43. aspodkfpo

    Energy loss in simple harmonic motion causes the time period to shorten?

    https://www.asi.edu.au/wp-content/uploads/2016/10/ASOEsolns2012.pdf Q11 D) Markers comments: Few students reached part (d) and very few of those who did realized that the amplitude does affect the time taken for each of Mordred’s bounces. i.e. the energy losses results in shorter periods...
  44. udtsith12

    Mass loss in Bernoulli's Principle?

    Hi, I could really use help. I am trying to understand what would happen to the velocity of a freestream air if it loses mass while traveling down a tube. For example, suppose that you have 1 cubic meter of air traveling at 10 m/s down a duct with a 1m^2 cross section. And then suppose that you...
  45. B

    Pressure loss pipe system: Conversion from known fluid1 to fluid2

    Hello, everyone, I am currently working on the following (real) problem, where I am not getting anywhere. It would be super nice if you could have a look at this. Thank you very much :-). I have a pipe system (Black Box) of which I only know the following things: At a set flow rate with a...
  46. T

    B How to create a parabolic formula - For Weight Loss

    Hello all I was hoping someone can help with the following problem. I am trying to create a parabolic formula to give me target weight. For example:- Day 1 = Target Weight 100kg Day 112 = Target Weight 67kg Each day is consecutive - can anyone help me to create a parabolic formula that goes...
  47. Y

    Engineering Find out the percent exergy loss

    Problem, with state values, and pie chart (Fig 4.20) showing answers: ^ This shows the system in question (Kapitza Liquefaction System). Methane gas enters into the compressor (c), then goes through the first heat exchanger (HX1). Some of it (z) gets routed to the expander (exp). Afterwards...
  48. M

    Engineering Power Loss Definition in a Damped Wave Equation (Skin Depth Problem}

    Hi, So the main question is: How to deal with power loss in E-M waves numerically when we are given power loss in dB's? The context is that we are dealing with the damped wave equation: \nabla ^ 2 \vec E = \mu \sigma \frac{\partial \vec E}{\partial t} + \mu \epsilon \frac{\partial ^ 2 \vec...
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