Loss Definition and 841 Threads

is science anywhere near being able to reverse hearing loss, like with stem cells or otherwise? it just terrifies me to some day lose my hearing an no longer be able to enjoy music as I do now.

i was doing a little thinking and have a pretty good idea but to see if it will even come close working i need to know how much energy loss is there converting water to hydrogen then back to water. using Electrolysis to split the water and a fuel cell to rejoin them back together. i know you...

Hi guys, can anyone help me with this question?- An optical fiber has a loss of 0.8dB/km at a wavelength of 1250nm. If 120uW of power is injected into the fibre at the transmitter, how much power would be lost at a distance of 20km down the fibre, also calculate the energy loss over a 24hr...

can anyone tell me that how to calculate corona power loss for bundled conductor? I need formulae of it.

1. The problem statement: A 5.00 x 10^2 kg object is attached by a rope through a pulley to a paddle-wheel shaft that is placed in a well-insulated tank holding 25.0 kg of water. The object is allowed to fall, causing the paddle wheel to rotate, churining the water. If the object falls a...

Hey all... My scenario is as follows: I have a pump that provides a certain rate of flow in my system. The pump is connected to a spraybar, a pipe with holes drilled through at evenly spaced intervals. Each of these holes is fitted with a 90 degree nozzle (effectively a miniature 90 degree...

What percentage of electrical energy is lost as heat by the transformer that supplies a house with 240V ac?

It seems the colder artic winters have been causing ozone damage. Warmer weather stops the ozone damage. Go Figure. "The first signs of ozone loss have now been observed in the Arctic this winter, and large scale losses are expected to occur if the cold conditions persist. Overall...

One kilogram of fat is equivalent to 30 MJ of energy. The efficiency of converting fat to mechanical energy is about 20%. a) Suppose a 75 kg person runs up the stairs of tall building with a vertical height of the 450 m, how much work is done by the person? b) If all the energy used to do...

Hey, If you have 3 pipes of different diameter flowing into another.. what needs to be true for the head loss in the 3 pipes to all be equal? ie Hf1 = Hf2 = Hf3 Cheers. :S

Hi all I found values for heat transfer from a pool on the following website: http://www.engineeringtoolbox.com/heat-loss-open-water-tanks-d_286.html can someone please tell me how reliable is this information? especially that they didn't mention free natural convection, or is it...

A 575 kg satellite is in a circular orbit at an altitude of 550 km above the Earth's surface. Because of air friction, the satellite eventually falls to the Earth's surface, where it hits the ground with a speed of 2.10 km/s. How much energy was transformed to internal energy by means of...

Homework Statement A high-voltage transmission line with a resistance of 0.30ohm/km carries a current of 1050 A. The line is at a potential of 670 kV at the power station and carries the current to a city located 164 km from the station. (a) What is the power loss due to resistance in the...

Why doesn't the Earth lose it's atmosphere eventually? I realize that gravity generally keeps the atmosphere close to the Earth but over a long period of time I would expect that we would lose some amount to the vacuum of space and the solor winds. Over millions of years we would lose it all...

What is the most practical method of measuring where a home is losing heat? The idea is that these measurements would be the first step in calculating the most cost-effective improvement, deciding whether to increase insulation in ceiling, walls or floor, to upgrade to double glazed windows...

Homework Statement A 1200-kg car traveling initially with a speed of 25.0 m/s in an easterly direction crashes into the rear end of a 9000-kg truck moving in the same direction at 20.0 m/s. The velocity of the car right after the collision is 18.0 m/s to the east. (a) What is the velocity of...

Homework Statement A ball with original momentum of +4.0 kg*m/s hits a wall and bounces straight back without losing any kinetic energy. The change in momentum of the ball is? Homework Equations p (momentum) = mv Impulse = change in p/change in t The Attempt at a Solution I...

Homework Statement assuming that the temperature inside is T_in = 20 C and the temperature outside is T_out = 0 C. The walls and uppermost ceiling of a typical house are supported by 2*6-inch wooden beams (k_wood = 0.12 W/m /K) with fiberglass insulation (k_ins = 0.04 W/m /K) in between. The...

This might be stupid but I was thinking, when two subatomic particles collide at very high speeds, they form a bigger particle whose mass is less than the sum of the smaller ones, and the mass lost transforms into energy as in Einstein´s equation E=mc2. What happens with non subatomic...

In a normal water based heating system (boiler, radiators etc) I'm told that having a high pressure-loss over the radiator valves is a good thing? I'm just having trouble seeing why, since I always considered pressure-loss as the enemy (head-loss etc). Why is this good? Also, I hear that...

Ok so the question is, "A skier of mass 60kg, initially at rest, slides down from the top of a frictionless, icy, hemispherical, mountain with a radius of curvature R of 100m. a)Draw a free body diagram and write the Newton's Equations at the moment when he/she is at some point below the...

I've got a turntable whose bearing is frictionless rotating at a certain speed. A mass of clay is dropped on to it and sticks a certain distance from the center. I've been able to calculate the new angular speed of the turntable after the lump falls on it, but the follow up question is to...

Hi, I am doing a chemistry lab writeup, and I have an issue with my loss in mass. I measured the mass lost by plastics exposed to various pH levels (sulfuric acid conc's) and I have conclusive results. The expected patterns are visible in the results; however, since the pieces of plastic were...

Hello, I was wondering if anyone knew a calculation or method to determine the amount of current moving through a given material, knowing the resistance of the material, the specific heat and the temperature (while the material is actually being heated by current). Thanks, -scott

Hi, I believe that the free electrons in a piece of a conductor move randomnly until they are oriented in one particular direction by some external field. Does free electrons lose energy in this random motion??:confused:

What formula should i use to calculate the loss in kineti energy during braking and the power dissipated as heating in the brake do i just use ke=1/2mv^2 and work done =force x distance ?

NLP and weight control have more to do with the way you think about food than food itself. The NLP Weight Control Program has three fundamental keys that make it work. The first being realigning your attitude about yourself first, your self image and your inner voice. The second is...

Lets say you have a ball on a ramp (hight h). It rolls down to the ground and then starts moving at aconstant speed - no friction (ok don't kill me, it's not really rolling either, just sliding). Now to the point of view of someone moving at the final speed of the ball and in the same...

I was reading on this page... http://www.cda.org.uk/megab2/build/pub125/sec4.htm#5.1 ...and I tried calculating head loss using both the forumla given, and the nomogram. Aren't these supposed to give the same result? Or am I missing something fundemental? Because they don't equal each...

For want of a nail, the Kingdom was lost!

I remember reading an article many years ago that there was a theory that part of the red-shift we observe from far away galaxy's could be do to a time (or distance) related reduction in frequency of light, in addition to the "doppler" effect. Has this theory ever re-surfaced again (it may have...

Sir, A man covers his body with a blanket of thickness 4 mm. His temperature is 37 degree Celsius and that of the atmosphere is 27 degree Celsius. If the coefficient of thermal conductivity of wool is 1.2 x 10^(-5) W/m.K , what is the heat lost per hour per square meter area? I solved it...

Sir, Two bodies one hot and other cold are kept in vacuum. What will happen to the temperature of hot body after sometime? I think that the temperature of the hot body decreases due to radiation as it needs no medium. But the book answer says that it will remain constant. Which is correct?

Hi all, I'm having a problem with this subject and I was wondering if anyone could confirm/comment on my understanding. As I understand it, in a typical transformer, an AC current is supplied to a primary coil which induces an oscillating flux within the core. If the core is made of a...

This was a question posed to me by a homeowner. I don't know very much thermodynamics and hope someone here might have a better understanding. They have a run of 3/8in copper pipe leading from their water heater to various taps. On cold mornings, it takes a long time, for hot water to flow to...

Show that the power loss in transmission lines, PL, is given by PL = (PT)^2 X R/(V^2), where PT is the power trasmitted to the user, V is the delivered voltage, and R is the resistance to the power lines. I don't even know where to start. I am so confused by this chapter, I don't know what...

When middle C on a piano (frequency = 262Hz) is struck, the vibration of the piano string loses half its energy after 4s. (i) What is the decay time for the energy? (ii) What is the Q-factor for this piano wire? (iii) What is the fractional energy loss per cycle? SHM has been going great...

Hi! I have the following equation for the entrance loss from an open channel to a pipe, but I'm not sure how it was derived: hloss = K*(V2^2 - V1^2)/2g I have always seen entrance losses as: K*(V^2)/2g, but why is the channel flow velocity considered in the equation above. Thanks...

Hi! I have the following equation for the entrance loss from an open channel to a pipe, but I'm not sure how it was derived: hloss = K*(V2^2 - V1^2)/2g I have always seen entrance losses as: K*(V^2)/2g, but why is the channel flow velocity considered in the equation above. Thanks...

Okay, so we did a lab where we dropped a bouncy ball (mass = 56.4 g) from 1meter above the ground, and measured the height that it bounced up to. We need to calculate the: a) loss of energy due to the first bounce for each of the balls b) the speed with which the ball strikes the floor...

I weigh 200 pounds today on earth, now I go Into an Isolated System (Say, an artificial Satellite) for six months, I eat healthy foods, drink a lot of water and regularly exercize (due to lack of anything else to do :D), so I'll lose weight, and hence mass. 1) Will there be any change in the...

A room is 5x5x5=125 m3 and holds a temp of 30C. On the other side of all the walls the air is 20C. I measure that the room temperature drops about 0.001C per second. If I now use this equation... \dot Q = V \cdot C_P \cdot \rho \cdot \dot T ...I get the amount of heat that needs to...

A copper sphere of 8cm diameter is blackened and suspended from the ceiling by a fine thread in a room kept at 25 degrees C. The sphere is then heated to a temp of 147 degrees C. Calculate the net rate of heat loss by the sphere. Im not given any constants such as stefans or the emissivity...

I have two mirrors at the same height on opposite walls facing each other in my bathroom. I took a laser pointer and put it in between the mirrors and directed the beam at one, such to where the reflected beam hit the other mirror, and back on the first and so on. Anyway, I noticed probably 16...

Help! Heat Loss! A cup of coffee (with a lid) is enclosed in an insulated cup 0.5cm thick in the shape of a cube 13.1cm on a side. The thermal conductivity of the cup is 0.0002 cal/s*cm*DegreeC. The temperature of the coffee is 87C and the temperature of the surroundings is 14C. Find the...

the incredible lifting machine heat loss?? While stumbling upon this website on the Incredible lifting machine, http://tigre.ucr.edu/dipen/phy11/heat.htm I was wondering what could be some of the reasons why the work down calculated as in mgh does not equal to the work done under the pv...

I need to show Integral( u(x, t)^2 dx from a to b) <= Integral( u(x, 0)^2 dx from a to b). In other words, energy is lost with time. This is what I have so far, but I get stuck near the end. Let F(t) = Integral( u(x, t)^2 dx from a to b) F(t) - F(0) = Integral( dF/dt dt from 0 to t)...

MK asked on another thread how a particular frog ties into climate change. I responded and provided a general connection between types of plant communities and the carbon they can "sink" from the atmosphere, and allusions to how loss of habitat in general is contributing to despeciation (in this...

Hi, I do not know how to drive an experession for energy loss of damped oscillator.I know that: X(t)=A exp(-Beta*t)cos(wt-delta) and: v=dx/dt... I found E=K+U but it seems to be so messy. It is like: E=(1/2)*m*(A^2)*exp(-2*beta*t)[ beta^2 (cos(wt-delta))^2)+beta* sin...

During pregnancy, a woman's weight naturally increases during the course of the event. When she delivers, her weight immediately decreases by the approximate weight of the child. Suppose that a 120-lb woman gains 27lb during pregnancy, delivers a 7-lb baby, and then, through diet and exercise...