Per Definition and 545 Threads

okay so here is the problem and here is wat I did! I am just tryin to study up for exams now... and this is one of the problems! A sample of blood is placed in a centrifuge of radius 17.5 cm. The mass of a red corpuscle is 3.00×10-16 kg, and the magnitude of the force required to make it...

So I start getting about 10 popups per second(popping up in IE, which I thought I had deleted) so I go to my computer, and I have at least 20 files that are certainly spyware. I'm able to delte al but 2, but the other ones I don't have access to I restart the computer in safe mode and I...

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...

I'm attempting to answer these thermodynamic quesions about entropy. It's been years since my last thermo course so knowledge is cloudy. If I'm incorrect or missiong relevant answers, please help. a. If ds = 0, what can you say about the process? b. If ds < 0, what can you say about the...

Could the size of our universe be determined by some average per volume temperature ?

Carmel owes $2902.40 on her bankcard. (a) If the interest rate is 15.5%, how much interest will she pay per year? (b) Interest is calculated dail at 0.04246% and charged monthly. How much will Carmel pay for a 30day month? (c)If she pays $500 off her bankcard bill on 15th July, how much...

Just trying to interpret some units here. If J/s is Watt, what does J/(s^2) tell me?

'A radioactive element has a 0.5 probability of decaying to a more stable element after a particular time-span T. What is the instantaneous decay rate per unit volume? In other words determine a general expression for the number of decay events occurring per unit volume between t=t1 and t=t2...

How many flip-flops do I need based on the following requirement? I'm thinking 2 flip-flop since each flip-flop can be a 0 or 1. So each flip-flop holds 2 states. Design a clocked synchronous state machine with two inputs, X and Y, and one output, Z. The output should be 1 if the number of 1...

hi everyone I was wondering why do fats contrain the most energy per gram?

A centrifuge is a device in which a small container of material is rotated at a high speed on a circular path. Such a device is used in medical laboratories, for instance, to cause the more dense red blood cells to settle through the less dense blood serum and collect at the bottom of the...

We might set up an experiment at University shooting photons one per second through slits. I think this experiment was done long ago and proved that light was a wave that was everywhere in that the photon seem to trave through both slits at the same time. But I read in the Halliday, Resnick...

Could someone explain undulation per revolution? I would prefer to have a mathematical function defining it also if possible. Can any explain ONE also? .

does anyone know what power output the best current betavoltaics can produce per size per volume/type/radioactivity of fuel? Are they capable of size for size equaling a normal battery? and if not what fraction of the way there? or are alphavoltaics more promising? I cannot find much of interest...

Could anybody tell me, in whatever units, how much energy per volume (and by mass if you know) is released by the most powerful chemical reactions?

a) Find the total power radiated into space by the Sun, assuming it to be a perfect emitter at T = 5690 K. The Sun's radius is 7.0 108 m. (b) From this, determine the power per unit area arriving at the Earth, 1.5 X 10^11 m away. the formula for radiation is Power = (emittance...

Hi, guys! :approve: My exam comes in one week, so I need your urgent help :cry: I found out, that one of the problems in the exam will be about convertion between rounds per minute (of a CD or HDD) and megabits per second (as reading speed). I have no idea what is the dependence between...

Hi everyone--I'm a bit stuck trying to follow a calculation in an article (Nucl. Phys. B360 (1991) p. 145-179) regarding the lab-frame relative velocity of two colliding particles as a function of the kinetic energy per unit mass. (I'll include references to equations in the article, but the...

for example user puts in the month as 1-12 the day for whatever month and the year, which has to include leapyears leap years only occur when the year is divisible by 4 y%4==o or if divisible by 400 but NOT 100, so 2000 is a leap year but not 2100 so if somebody puts in month 1 day 1 and...

this has probably been done before, but ayway... I'll start off a story with four words. the next person who posts will continue the story with 4 more words and so on. I'll start: there once was a...

I don't get it. Africa is the poorest continent on Earth, with a veritable panoply of plagues. The U.S., being the richest, is also the most shameful for its parsimony towards these suffering. What does this tell us of George W. Bush's charitable beliefs? The Iraq debacle consumes...

An engine with an output of 150W has an efficiency of 25%. It works at 10 cycles/s. A. How much work is done in each cycle? work=power(delta t) = 150 W * 1s = 150 J work =15.0 J per cycle **got part A correct B. How much heat is given off in each cycle? delta...

If the annual consumption of petroleum in the US is about 23 barrels per capita, the total annual consumption of petroleum in the US is closest to: 1. 12 mill barrels 2. 240 mill barrels 3. 2 billion barrels 4. 6 bill barrels 5. 10 bill barrels I don't know what is meant by "capita."...

Having trouble with a thermodynamics problem I'm having a bit of a problem with some of the homework in my thermodynamics class. Question (Water at 20 C, 100 kPa is compressed isothermally to 50 MPa. Determine the work required per unit mass. ) using the tables I found: State 1 T_1=20C...

Watts per squ meter?

Can anybody explain it to me?

hi I'm doing a question involving the mass of a blanket ... I just need to know the following : could somebody please tell me : what it means by mass per unit area ? and for a blanket, how is the mass/unit area measured because the blanket is soft ? Roger

From MSNBC: GR confirmed again as gravity measurements reflect the predicted space-time dragging effect caused by spinning objects. A research team analyzed millions of laser signals bounced off two satellites, called LAGEOS and LAGEOS 2. Both are highly reflective spheres not designed to do...

An electron of mass (m=9.1*10^(-31)kg) orbits a proton at a distance of 5.3*10^(-11)m. The proton pulls on the electron with an electric force of 9.2*10^(-8)N. How many revolutions per second does the electron make? This is what I did: m=9.1*10^(-31)kg v=5.3*10^(-11)m T=9.2*10^(-8)N...

i read somewhere that pressure is the change in force per unit of area and can be represented as the derivative P(A) = dF/dA but in order for it to be the derivative shouldn't it be P(A) = dF/dA lim dA -> 0

Kerry wants more efficiency with our automobiles. I predict he'll win on this point in the debates, if it's capitalized upon. Why? Any energy saved because of more efficiently built autos is energy that could be directly invested in things elsewhere in the economy. The consumer price could...

Is fructose a less caloric sweetener than sucrose or dextrose?

Why doesn't each state count as 1 electoral vote for the presidential elections. Then their would not be pivotal states at all. It seems like the president would not get elected mainly by the most populated states this way.

Can some one help me with these two questions? I am unclear how to do them! Thanks :smile: 1. A 27.2g peanut is burned in a bomb calorimeter, and the temperature of the surrounding 100g of water rises from 24.25 degrees C to 26.87 degrees C. Given that the calorimeter constant is...

If one is seeking to explain everything, doesn't one run up against Goedel's incompleteness theorem?

Hey guys, simple question about binding energy. I'm asked to find the average binding energy per nucleon of Magnesium-26. Now I thought that I would have to use: Binding E = (Zmp + Nmn - Ma) X 931.494 MeV/u. Where Z is the atomic #, N is the # of neutrons, mp, mn, and Ma are mass of proton...

I would like to know how much ATP is created per hour, per day , during the day, during the night in humans. What is the correlation between ATP and body mass? Does diet, age and exercise effect ATP generated? Reena

i am new to this forum..a programmer who deals with server and related stuff i like to know how much bandwidth this forum takes a day and how many hits a day?

Simple Question to all of you : How many E-mails do you Send per week ? Hope this one works, and thanks Zero :wink:

if there are 1000 GRBs per day, where is all that energy going, is our universe getting more energetic or is it so big that it can adsorb this energy with no aparant change?

Which page of which thread has the greatest number of distinct PF Mentors posting to (on?) it?

Hello, again. I have a question problem, fairly simple, that I have most likely done wrong. It is about a pool leak. When the pools water pump is on, from 3:50pm to 10:10am the pool lost 2.25in. When the pump was turned off from 10:10am, to 1:50pm, it lost 7/8 in. They want to know how...

How many revolutions per minute would a 15m diameter Ferris wheel need to make for the passengers to feel weightless at the topmost point?

Or is it Nebulae...anyways What is the density in atoms per unit volume of most nebulas? I am just looking for a rough estimate to help me picture it.. And what would it look like if u were inside one..would u even see anything?

One calorie per cubic mile is almost exactly the same as one joule per cubic kilometer. Because a calorie is 4.185 joules and a cubic mile is 4.166 cubic km. And the density of the universe has finally been measured to the general satisfaction of astronomers, at 0.85 joule per cubic...