Loss Definition and 841 Threads

  1. C

    Can spinning an object fast enough make it weightless?

    Wonder chick have a question again today. I heard from doucumentary that when object is spining, It's bit lighter than when it stop. My understand is because Weight distribute to orther vecter than going down to gravity. So, Is it possible that object can spin fast enough to Its weight...
  2. F

    At a total loss with these Galois groups.

    I've been asked to match some galois groups with structures like: Z_2, Z_3, Z_2 X Z_2 ...etc. And I'm very much lost. I know the galois group for a field extension L:K is the set of isomorphism that fix F. These form a group with function composition. OK. But how do I find these isomorphism...
  3. B

    Heat loss of a steel steam pipe

    I have a heat transfer question, I work in a plant and am doing a re-insulation project. If an unexposed steel steam pipe (k=47) of diameter 10 inches, maintains an internal temperature of 460F and is exposed to ambient air (70F) flowing at 5 mph across the pipe. Determine the heat loss per unit...
  4. D

    Finding Kinetic Energy Loss in Equal Mass Collisions

    Homework Statement How do you find the kinetic energy lossed when you have equal masses in a collision problem? Homework Equations The Attempt at a Solution
  5. B

    Loss of momentum in supposedly isolated inelastic collsion?

    I may have made a mistake in calculating, but I just finished lab homework where my calculated momentum was different before and after an inelastic collsion. Is it possible that momentum was lost in the vibration of the impact or something? The experiment placed two gliders on a level air...
  6. P

    How Much Power Is Lost Due to Resistive Heating in a High-Voltage Line?

    Homework Statement A 750-MW power plant sends its power out on a 475,000 V high-voltage line. If the total resistance of the line is 0.65 Ω, what percentage of the power is lost due to resistive heating? Homework Equations i have NO idea but maybe... P(loss)=I²R P(loss)=^v²/R...
  7. S

    Mechanical Energy loss due to NC Forces: two railroad cars collide.

    [SOLVED-Thanks AL]Mechanical Energy loss due to NC Forces: two railroad cars collide. SOLVED! - Thanks Al! Homework Statement Two railroad cars each of mass 4800 kg and traveling @ 80 km/h collide head on and come to rest. How much thermal energy is produced in this collision? Homework...
  8. C

    Calculating Energy Loss in a Hockey Puck Collision

    Homework Statement One hockey puck of mass 0.2 kg strikes an identical stationary puck on a frictionless ice rink. If the first puck had a velocity V0 = 3.8 m/s before the collision and V1 = 1 m/s after in the same direction, what fraction of the energy was lost? Homework Equations...
  9. P

    Conductive Heat Loss in a house

    Homework Statement If only conductive heat loss was significant for a house, then by what percentage would you lower the heat loss if the temperature was reduced inside from 73°F to 67°F, when the outside temperature is 21°F? (Hint: Try using a ratio.) Homework Equations Unknown The...
  10. E

    Thermos Heat Loss: Solving Differential Equations for Changing Temperatures

    Homework Statement A thermos consists of two layers (see fig). The core contains a liquid with temperature T_1. The outer layer contains air at low pressure with temperature T_2. The surrounding air has temperature T_3. At t=0, T_2=T_3. Assume that T_3 does not change with time, and that...
  11. A

    Understanding Gear Windage Loss

    Dear all Anybody define,what is exactly gear windage loss? Text books defined that loss due to lubricants etc...vague Thanking u Prakash
  12. S

    Heat loss from an insulated water tank - Thermodynamics

    Heat loss from an insulated water tank ----- Thermodynamics Hi and thanks in advance for any help with this problem. If I have a very very well insulated tank of water of say 4 litres. If we could assume that the tank had no heat loss... The tank is heated by an electrical device that...
  13. G

    Double Glazing: Heat Loss Explained

    I understand that double glazing reduces heat loss by minimising conduction of heat from the interior pane to the exterior one. Air is a very bad conductor so the heat does not travel from 1 pane the other very easily. Is that correct? If so, why doesn't all the heat just build up in the space...
  14. M

    Loss of information in tangents

    why is there a lack of accuracy in this subsitution? \frac{sin\phi}{cos\phi} = tan\phi
  15. S

    How can i figure the current loss of a power supply?

    OK, so if I'm inputting 120V ac @ 1.5A equals 180W and my output is 19V dc @ 3.16A equals 60.04W simple subtraction says 116W is left. that can't be right can it? am i doing this wrong or am i actually losing 116W of power?
  16. T

    Transformer copper loss calculation

    Hello guys have a little problem see if anyone can help Homework Statement Q the primary winding resistance is 125Ohms, Secondary is 0.7ohms calulate the transformers copper loss at full load. now the transformers name plate is 240V 50Hz 28VA the earlier question explains...
  17. C

    Calculating Rate of Heat Loss for Metal at 800K

    Homework Statement A metal (doesn't say what metal) is in a heater that is set to 700 K. If the temperature of the ball is 900 K then the rate of heat loss = 0.10 J/min. What is the rate of heat loss when the ball's temperature = 800 K. The ball's emissivity doesn't change appreciably with...
  18. J

    Generator loss of exitation protection

    I am trying to protect a generator fro loss of field with a reverse KVAR relay. My question is does a reverse KVAR relay's current transformer need to be upstream or downstream of AVR's connection to line voltage? (AVR is automatic voltage regulator) Does it matter at all.
  19. F

    How Can I Calculate the Pressure Loss Coefficient of a Diffuser?

    Hi, I want to calculate the pressure loss coefficent for a diffuser but I can't find the equation. I tried with bernoulli but I don't get it. I've read that the coefficient depends on the length the scale and conical degree of the difuser? Can you help me? thank you!
  20. P

    Energy loss in the doppler effect?

    If the energy of an EM wave = h x f and when a light emitting body (of a particular power) is moving toward or away from the observer the observed frequency changes, does the energy change? If so where does the gained or lost energy come from?
  21. N

    Information loss via black Holes

    This question is about the relationship between information, entropy and heat. I think it was in the 1970's the Hawking claimed "information is lost in black hole evaporation". This did not mean it was just inaccessible, but that it has literally disappeared, gone forever. In the Black...
  22. M

    Need a formula to calculate BTU loss in a pond.

    I am looking at building an ortemental pond. The pond will be 15' x 3' with an average depth of 2'. I caculated it out to 673 gallons and 45 square feet of surface area. I plan to put tropical fish in it and will have to maintain a temperature of 72F year round. Worst case scenario would be an...
  23. J

    Calculating Power Loss in FSO: A Study of Free Space Optics

    Homework Statement Well, I´m doing a project about FSO (Free Space Optics), it deal with optical communication but without fiber, only by air. Then, I have already studied the transmitter (gaussian source), the channel and I know I need a photodetector APD for the receiver but my questions...
  24. M

    Energy loss without displacement

    Hi, This is about a basic fact which has never been clear to me. As per the equation Work = Force x Displacement, if there is no displacement there is no work. On the other hand, one of the exercises I do involves pushing a wall. I stand in front of a wall and try to push the wall as...
  25. J

    Power Loss In Transmission Lines (Again?)

    Edit: My question is better expressed in my next post so ignore this post. Homework Statement A power station delivers 890 kW of power at 12 kV to a factory through wires with total resistance 5.0 \Omega How much less power is wasted if the electricity is delivered at 50 kV rather than 12 kV...
  26. W

    What are the best transceiver options for low data loss during transmission?

    Hi! Recently I done some survey on transceiver, may I know if a transceiver which data rate is 1.2kbps and a transceiver with data rate 19kbps, which transceiver will loss more data during transmit? Can anyone recommend me a suitable transceiver?(data rate high, loss of data low) thanks!
  27. J

    Calculating Power Loss in a 300 MW Power Station

    Homework Statement A 300 MW power station produces electricity at 80 kV which is then supplied to consumers along cabes of total resistance 5.0 ohms. What percentage of the power is lost in the cables. Homework Equations P = VI = V2/R The Attempt at a Solution I said the total...
  28. M

    Conservation of momentum and loss of energy in inelastic collisions

    I just learned that, in elastic collisions, the total momentum in the system is preserved while a certain amount of kinetic energy is lost. I know that kinetic is energy may be lost in the form of heat or sound. Isn't the same energy responsible for keeping the two objects in motion and...
  29. A

    Avoid Loss of Significance in Function: Tips & Advice

    Homework Statement Hey guys. Anyone knows how can I avoid loss of significance in this function? http://img402.imageshack.us/img402/4216/33365715.jpg Thanks a lot.Homework Equations The Attempt at a Solution
  30. S

    Energy loss: trouble with signs?

    Homework Statement picture: http://is.gd/tm7a An apparatus to determine coefficients of friction is shown above. The box is slowly rotated counterclockwise. When the box makes an angle \theta with the horizontal, the block of mass m just starts to slide, and at this instant the box...
  31. M

    How Do You Calculate Power Loss in High-Voltage Transmission Lines?

    Homework Statement A high-voltage transmission line with a resistance of 0.345 ohms /km carries a current of 1.05 kA. The line is at a potential of 600 kV at the power station and carries the current to a city located 173 km from the power station. A>What is the power loss due to...
  32. I

    Calculating of heat transmission loss (convection) in a thick glass plate

    Hi. Do anybody here know how much and how quick a 50-100mm thick tempered glass plate of size 500mm * 500mm fully heated up within its bulk mass to a temperature of 60 degrees celcius looses it heat energy/temperature over time when surrounded by standing ambient air (20 degrees celcius)...
  33. B

    Why Does Magnetic Hysteresis Loss Appear as a Resistance in Electrical Circuits?

    Hi Guys, :smile: Can someone please explain to me the logic behind the representation of 'Magnetic Hysteresis loss' as a resistance in electrical equivalent circuits?... will be extremely grateful. I have studied some info on this subject on the net. Even though the physics of Hysteresis...
  34. D

    Which statements about heat flow are true?

    Homework Statement Which one of the following statements about heat flow is FALSE? (A) Thermal conduction is due to energy exchange during collisions of atoms or molecules. (B) Thermal convection occurs only in fluids. (C) The rate of heat flow due to thermal radiation is proportional to the...
  35. B

    Why Is Magnetic Hysteresis Loss Represented as Resistance in Equivalent Circuits

    Hi Guys, :smile: Can someone please explain to me the logic behind the representation of 'Magnetic Hysteresis loss' as a resistance in electrical equivalent circuits?... will be extremely grateful. Thanks & Regards, Shahvir
  36. J

    Can sudden expansion loss coefficients be summed?

    I was wondering since I'm trying to figure out an equivalent loss coefficient for a manifold that has a specific geometry. I have several area sections and would like to know if I can just add up the resulting loss coefficients from one section to the other. Any help would be greatly appreciated.
  37. I

    Power loss in transmission lines problem

    Homework Statement A power station delivers 890 kW of power at 12 kV to a factory through wires with total resistance 5.0 \Omega. How much less power is wasted if the electricity is delivered at 50 kV rather than 12 kV? Homework Equations eq-1) P = IV eq-2) P = I2R Ohm's Law...
  38. K

    Energy Loss & Height of Thrown Ball & Marble Fired from Cannon

    1. A ball with a mass of 0.5 kg is thrown straight up with an initial speed of 20 m/s. The ball reaches a maximum height of 15 m. (a) Give the energy loss due to air resistance. (b) What height would the ball have reached without air resistance? (c) What height would the ball have reached on the...
  39. B

    Calculating Kinetic Energy Loss in Neutron Collision

    I need help with this problem where we are suppose to determine the fraction of kinetic energy lost by a neutron m=1.01u when it collides head-on and elastically with a target particle at rest which is. examples used.. Hydrogen = 1.01u heavy hydrogen = 2.01u How would you do this? Do...
  40. S

    Capacitor charging loss (Not the two capacitor issue.)

    I got some guy who says when a capacitor is fully charged, that half of the input energy from the power source gets lost as heat. Now I do understand the two cap problem (links below), but I think he is wrong because one can use dc switching and inductors to improve the 50% loss of energy. (but...
  41. D

    How does high voltage decrease energy loss in a wire

    If you raise the voltage you must raise either the current or the resistance since V = IR. So how does a wire with higher voltage and lower current have less resistance? It should have more resistance to make up for the lower current.
  42. djeitnstine

    Is y=0 a Lost Solution in Differential Equations?

    When solving a Diff. Eq. how do we know that y=0 is another solution lost when we solved it?
  43. M

    Calculating Wavelength of Radio 4 FM & Explaining Loss in Deep Valleys

    Homework Statement Radio 4 transmits on FM at a frequency of 92.5 MHz Calculate the wavelength and use it to explain why listeners in deep valleys cannot pick up radio 4 FM. Homework Equations The Attempt at a Solution
  44. J

    Heat loss through an open door

    All the info I could obtain talks about heat loss through windows and doors. I am trying to get several store owners in my town to close there doors in the middle of winter and summer. The average door is 28 sq ft. I am assuming the inside temperature is 68 degrees and the outside temperate...
  45. M

    Waveguide loss measurement- endfire coupling

    Hi, I am doing an experiment to investigate the propagation loss in some nanophotonics structures. The laser light is coupled to the input of the DUT chip via a tapered lensed fiber and the output of the chip is go through a objective then a photodetector. The chip is design for...
  46. Danger

    John Travolta: Tragic Loss of a Teen Son

    I just saw on the news that John Travolta's teenaged son died of a siezure, which he had a history of. Whatever one might think of Mr. Travolta as an actor, or a (non-intrusive) Scientologist, or anything else, nobody should ever have to witness the death of an offspring. I happen to like his...
  47. J

    Calculating Head Loss from Enlargement in Compressible Fluid

    how to calculate head loss due to sudden enlargement in case of compressible fluid? hiiiiii guys, am graduate student, i want to know @ head loss in case of compressible fluid due to sudden enlargement...pls help me ...as soon as possible...
  48. T

    Heat Loss Question: Single Coin vs All Coins

    Homework Statement A stack of identical coins is all at a temperature of 100 C. The coins are transferred to a container of room temperature water. After thermal equilibrium is reached the final temperature is 35 C. The Heat lost by a single coin is less/greater/equal to the heat lost by all...
  49. G

    Internal combustion engine thermal energy loss

    Hello, I know that something around 65% of the potential energy stored in fuel is lossed in an engine through heat. I am trying to find exactly how its lossed, I know some is through piston friction, and some is lossed through the exhost, but I can't find how much is lossed for each...
  50. fluidistic

    Loss of mechanical energy in a plastic collision

    Hi all, Homework Statement I'm stupefied. In continuation to my last thread (https://www.physicsforums.com/showthread.php?t=277124), I wanted to see if any perfectly plastic collision would make the total mechanical energy of the system go down to a factor of \frac{1}{\sqrt 6}. I got a...
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