Loss Definition and 793 Threads

Homework Statement A glass window pane is 2.7 m high, 2.4 m wide and 2 mm thick. The temperature at the inner surface of the glass is and at the outer surface 4°C. How much heat is lost each hour through the window? The Attempt at a Solution I have the stats on the glass like...

Does 0.25 J or 0.0082 J seem like a reasonable loss of energy in terms of a 83 g ball rolling down a ramp?

Homework Statement How would you calculate the loss of energy down the ramp, given only the following information: Mass of ball = 0.0083 kg and http://i1097.photobucket.com/albums/g349/Physics_/Energy.jpg Homework Equations E = mgh E = 0.5mv^2 The Attempt at a Solution I...

Homework Statement A block of mass 7.00×10-1kg is suspended by a string which is wrapped so that it is at a radius of 5.80×10-2m from the center of a pulley. The moment of inertia of the pulley is 4.00×10-3kg*m2. There is friction as the pulley turns. The block starts from rest, and its...

For example, if I want to show that there is no real # solution to x2 + 24x2 = -1 is it correct to show that d2/dx2( x4 + 24x2 ) = d2/dx2(-1) ---> 12x2+48 = 0 And since x^2 is >0 or =0, 12x2+48 ---> 0 + 48 \neq 0 Therefore, there is no real number solution to x2 + 24x2 = -1...

[FONT="Comic Sans MS"] hello guys..! i have one pulley of 8" (Driver) and another one 10" (Driven) he driver pulley is driven by 2Hp motor, so is there any equation or formula to calculate the Hp loss or power loss from 2Hp?

Homework Statement An electron with energy 10^3 MeV collides with a photon whose wavelength corresponds to the maximum wavelength of the 2.7-K cosmic background radiation. What is the maximum energy loss the electron can suffer as a result of the collision? What is the wavelength of the photon...

Does the rate of heat loss remain constant during any period. I'm doing a lab on heat loss where I'm comparing the loss of heat in a aluminum soda can with hot water to a aluminum can with hot water covered with insulation material.

I am 9LBs overweight for my ideal BM, i all ready go to the gym 3-5 times a week. So what sort of food should i be eating.

Hi. Since photons lose energy when moving against gravity (because of gravitational redshift), there must be some other energy that is increased, i.e. the energy converts to another form. That other energy must be potential energy, right? But for a photon to obtain potential energy, it must...

Hi guys, the Bethe bloch (BB) equation, in combination with the material density, gives the energy deposited in the material per unit path length. One of the terms in the BB equation is the maximum energy transferred to an electron by the incident particle. So i am assuming, the...

I am working on an incubator/shaker for laboratory use. I am trying to work out a temperature failure and repair it, but that is besides the point here. I was looking through the user manual to try to get some clues about the failure and I came across this: "Depending on various conditions...

I'm trying to size (in watts) a heater to heat a glass of water from ambient (Ti) to a certain temperature (Tf) in a given time period (say, 1 hour). The heat-loss from the glass at Ti is 0 watts. The heat-loss from the glass at Tf is Y watts. I'm assuming that the heat loss increases...

Hey I am designing a pipe system for a class and am required to calculate headloss. At one point in the design, a pipe splits into 4 smaller pipes and then these rejoin to recreate a pipe at the original pipe. I can't seem to find the loss coefficients associated with the quadfurcation and...

Homework Statement A spherical star of uniform density p and radius R is formed by the condensation of the interstellar dust from large distance due to gravitational forces. Find the energy change that occurs at some intermediate stage as the radius increases from r to r+dr Hence derive an...

My sincere apologies if this is not the right place however I will pose the problem: Being a humble plumber rather than a physicist I am used to calculating pressure loss in copper pipework for hot water heating systems by determining the required flow rate kW/h / specific heat x delta T...

Is there any loss of energy of a particel (electron) while getting collission with the walls of a finite square/rectangular barrier? since there is a enormous no. of collision a particle takes.

In a field loss event, why does a shunt wound dc motor run away? From my understand of electric motor, the armature spins because it's magnetic field pushes/pulls against the field winding's magnetic field. If I remove power to the field winding, then shouldn't the motor slows down because the...

this is the formula for calculating core loss http://power.thayer.dartmouth.edu/pictures/function.jpg alpha, beta and k are constants that have to do with the material of the core. what are f and B, and what exactly does Pcore mean

can i solve for core loss of a cylindrical inductor by knowing the dimensions of it and the material it is made of?

I was watching a video on youtube and thought about how well dominoes transport energy from one place to another. As soon as you set off one, it seems like you should be able to knock over an infinite amount of dominoes, but could you really? How would you prove if the initial energy you put in...

Homework Statement Particle A with mass 2m and particle B with mass 5m move towards each other with speeds of 8u and 2u respectively on a smooth horizontal plane . After the collision , particle B moces with speed u in a direction opposite to that of the original direction . Find in terms of...

Hi, I am using a 3 phase BLDC Motor. The scenario is, "When anyone of the phases to the BLDC motor fails, the hardware will disable the particular phase. My software should stop firing that phase." Thereby the motor should run with only 2 phases. Is this practically possible to run a 3...

I want to build a small geothermal cooling unit to cool one small room in my house. If i lay 0.5" pex pipe which is 0.475" ID. The big question is how long does the water flowing in the pex tubing have to stay under ground. Constant ground temperature is about 55 degrees F around my house. I...

Homework Statement Alright so I am doing a fairly simple experiment testing how the temperature of water in a beaker effects how fast heat is lost. Have done the tests, but need to get some predicted results to compare them too. Have been using a glass beaker filled with 200ml of water...

Hello, I am working on making an Excel work book to aid in figuring out pressure drops in a system. I am trying to use the Darcy Weisbach equation for pressure loss. http://www.engineeringtoolbox.com/darcy-weisbach-equation-d_646.html" In Excel I have =(C4*(C5/C6))*((C7+(SQRT(C8)))/2)...

I am working on a project at my summer internship rerouting some duct work and want to do some calculations to see how much changing some of the 90 degree angles in the duct will improve flow. I don't have my Fluids text with me and was wondering if anyone knew of any good references online to...

If the Earth's magma lost enough heat for it to solidify to a noticeable extent(permanent change, assuming irreversible), how would it affect its rotation about Earth's own axis and revolution around the Sun?

I found in a book the equation for the power loss caused by the heating effect of current in the transmission lines as below: Ploss = Iloss2R = (Pout/V)2R A friend of mine commented that the last bit "(Pout/V)2R" is unnecessary, confusing and wrong (but won't tell me why). Is my friend...

Hey I have a assignment to produce a excel work book to calculate acceleration time and top speeds for different gear ratios in race cars. I have so far work out time to accelerate to top speed, but I want to add a bit more detail to my graphs by showing the speed loss during gear changes...

Hi Guys, I have a problem about the loss coefficient. Head loss = K * (v^2/2g) Where K is the loss coefficients. This equation is base on Darcy-Weisbach equation. I wonder how is K varies for same flow rate, same device with a different viscosity and density. Thanks a lots in...

Homework Statement In an RC discharge circuit, R= 2.5 X10^4 ohms and C=40 microfarad. The initial potential difference across C is 25 V. Find the rate at which energy is being lost by C at 0.5 seconds. Homework Equations The Attempt at a Solution Like in this case, I probably have...

This might be a tired topic but please help me to understand. Assume a photon moving in vacuum, ignore potential interstellar medium absorption and re-emission since it is not relevant to discussion of space expansion in this context. Redshifted photons will undergo energy loss between *right...

Hello - just discovered this forum, which has been a big help since I graduated ME 15 years ago, but never had an opportunity to practice "real" engineering...until now. I am trying to develop a spreadsheet that models friction loss, using the derivation of Bernoulli's equation, over a nozzle...

Homework Statement http://i43.tinypic.com/i1bq1i.jpg I need help with number 9 Homework Equations Wnet=change in KE Wnc=Change in Energy The Attempt at a Solution I haven't been able to get the answer marked by the computer. I tried Fs(h*cos15)=.5mv^2-mgh and that is way off...

This is probably a dumb question, but I only need to know for a program I would like to write. Basically, on average (I realize there are a lot of factors involved, but a rough estimate is all I need), how much energy dissipates over a specific length of a conductor (power lines, whatever...

Hi All, I know that when water pass through a 90 degree bend pipe, there will be a pressure lose. However, how to calculate the energy/potential loss for electrical current pass through a 90 degree bend wire/resistor. Academic paper appreciated! THanks

Homework Statement For the LEP, we are given that it is a perfectly circular accelerator with circumference 25 km and that the energy of each beam is 50 GeV. Calculate the energy lost in GeV/s by a single electron on each turn. Homework Equations The loss is given by...

Homework Statement Assume no friction. A 58-kg teenager at a water park slides down a long, winding waterslide of varying slope. The slide has a net height difference of 30. m from start to finish, and the teenager starts from rest. Throughout the problem, let y=0 and Ugrav = 0 at the end...

How transformer loss vary with load current?

I've been attempting to spec a toroidal inductor--what core size, what material and how many turns? I happen to be looking at some made of the material Kool Mu. The material if ferrite, so I presume most of the core loss is hysteretic BH loss, as ferrite doesn't conduct well. Anyway, all...

Hello, I'm engineering a heat-pump for my senior project. My professor is out of town and these questions have been on my mind. I'm trying to calculate ACTUAL heat loss through the tent walls and ceiling. I'm using a tent 10ft x 5ft x 6ft. I'm trying to heat it with approx. 750 btus/hr...

Feet first... How do I calculate heat loss by evaporation from the surface of a swimming pool, at a range of temperatures and given a range of conditions? Any help gratefully received! Nick

Homework Statement What is the dB loss for a 3GHZ EM wave traveling through 2 meters of a medium with ϵ=1.5ϵ_0 and loss tangent = 9E-4? Homework Equations Umm...I'm actually not sure. I can't find anything really relating these things at all. The Attempt at a Solution My first...

Hello everyone, Quick question. When there is a pipe and you constrict it there is higher pressure loss. Is this pressure lost permanent? What is this pressure loss, is it loss as heat, are liquid molecules converted to heat, are they lost? What happens to liquid molecules if the hydrostatic...

How can I tell the difference between a free electron that's absorbed one photon at E = hf and a free electron that's absorbed two photons at E = .5hf? If a photon at frequency f represents a '0' and a photon at frequency .5f represents a '1', then I could send out '11', have an electron...

I’m an entrepreneur in South Africa with the rights to a type of insulating coating. It’s new on the market here and no real research and development has been done on the coating to determine how much energy it can save. I’m a marketer and I don’t have the educational background to answer this...

How can I calculate energy loss from a leak in a large furnace? I currently am working on a large furnace about 1200 square feet. To heat the furnace we use a combination of air and methane at a ratio of 9.54:1. There is currently a hole in the furnace and I would like a formula to calculate...

Homework Statement A 10/1 stepdown tranformer has a full load secondary current of 50A and is rated 30kVA. The copper loss at full load is 280W. The primary winding has a resistance of 0.25ohms. The core losses are 120W. Find the resiatance of the secondary coil and the power loss in the...

Homework Statement If the specific heat capacity of water from an experiment is smaller than its actual value, does it mean more heat is lost to the surroundings? If the heat is emitted by a wire into a cup of water and the change in temperature is measured, does it mean that the change in...