Loss Definition and 793 Threads

Hi could someone tell me if it is possible to calculate the shear loss from a metal piston ring against the cylinder in a hydraulic pump when the outlet pressure and speed (in rpm) of shaft are known. Cheers (Updated: maybe along the lines of in cylinder pressure x piston speed x friction...

Homework Statement We are heating up the cabin log with a furnace that has strength of 4 kW. The surface of the walls of the log cabin is 35 m². What is the temperature in the log cabin, if the outside temperature is -20 °C? The thermal conductivity of wood is 0.4 W/mK; the average wall...

Homework Statement Find the mass of liquid lead at fussion temperature needed to heat up 1kg of liquid water from 20ºC to 60ºC, considering P = 1 atm, and a loss of 100 mg of water due to local vaporization. My question is: what do I do with that loss of mass? Do I calculate Q for m =...

Hi all, Is there a definite relation between un-balanced loading of a 3 phase transformer and increase in transformer loss? If so, how? Does un-balanced loading affect variable (copper) loss or fixed (core) loss? Pls. explain in detail. If I carry out load balancing between the o/p phases...

I have a large circular tank made of concrete that has a volume of 9,300,000 litres. The diameter of the tank is 48.7 meters. The side wall of the tank has a height of 4.57 meters. The tank is set into the ground by 3.57 meters and 1 meter of the tank protrudes from the ground. The tanks'...

Homework Statement If 10 kilogram of ice at zero degrees celsius is added to 20 kilogram of steam at 100 degrees celsius, what is the temperature of the resulting mixture?Homework Equations uhm... perhaps how many solutions are required to arrive at the answer?The Attempt at a Solution I and...

Dear guys I need assistance regarding optimization problem. I have to minimize the power loss in worm gear drive system. I have formulated minimization function,and constraints,how to solve the function and find design vectors. ANy suggestions,sites,ref.welcome Thank u Prakash

A system emitting gravitational radiation loses mass. But how is this explained in terms of the system. Take for example a neutron star with non-radial oscillations - this will emit gravitational waves, and lose mass. So does the number of particles in the star decrease? Or does the binding...

I have air flowing through a gate valve with lengths of pipe of matching diameter upstream and downstream. At a certain distance from the valve upstream and downstream, I am measuring static temperatures and static and stagnation pressures. I can estimate the Mach numbers at the tapping points...

I have to find the kenetic energy lost in the problem. I have both initial and final kenetic energy, how do i calculate the percent loss? I tried final over initial times 100 but that is not correct.

Homework Statement PART D this is an example from my textbook, i do not understand the result however Homework Equations U = W = Q^2/(2v) = 0.5 CV^2 = 0.5 QV the charge once connected Q1 640 micro F Q2 320 micro F V1=V2 = 80V (equating the charges to total Q0...

A spring has an unstretched length of 0.650 and a weight of 0.400kg is attached and gently lowered till eqm point is reached. The spring is then stretched by a distance of 0.200m. Loss in gpe=mgh=0.200x0.650x9.81=0.785 J Gain in EPE=0.5 Fx= 0.5 x 0.400x 9.81 x 0.200=0.392 (?) Actually I...

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...

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...

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

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...

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...

[SOLVED-Thanks AL]Mechanical Energy loss due to NC Forces: two railroad cars collide. SOLVED! - Thanks Al![/color] 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 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...

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...

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...

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

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...

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...

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

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?

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...

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...

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.

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!

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?

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...

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...

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...

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...

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!

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...

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...

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

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...

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...

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...

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...

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

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.

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...

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...

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...

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...

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.