Per Definition and 545 Threads

Homework Statement In this calorimetry experiment, O.5 grams of magnesium is dissolved in 100.0 ml (100.0g) of diluted HCL (0.1mol/L) at an initial temperature of 29.50 C. The final temperature is 46.18 C. Q: Calculate the enthalpy change per mole of magnesium. Homework Equations...

This was a question I had in another post, but the main topic was on a similar but different issue... If I had the dimensions joules per metre squared per second (e.g. like for a solar panel), how would I write that? I've been told \frac{Js}{m^2} But I get \frac{J}{m^2s} Why is it...

Homework Statement Calculate the heat of reaction per mole of water formed in the acid-base reaction. Assume that the total mass of the solution is 150g. 75mL of 2.0M NaOH added to 75mL of 2.0M HCl in a styrofoam cup. Average initial temp = 295.65K. final temp = 308.8K Homework...

http://www.tuhep.phys.tohoku.ac.jp/~hotta/extended-version-qet-review.pdf In the link above and by searching net with "Masahiro Hotta", anyone can find papers written by him on energy teleportation. As per Hotta, energy can certainly be transported from Point A to Point by entanglement and at...

I know power = Torque x angular velocity (rad/s) AND I am wondering if angular velocity can be calculated through strokes per minute? The product is a reciprocating saw (not orbital). In this case are RPM's the same as SPM'S? Thanks

Homework Statement When jogging strenuously, an average runner of mass 68kg and surface area 1.85m^2 produces energy at a rate of up to 1300 W, 80% of which is converted to heat. The jogger radiates heat, but actually absorbs more from the hot air than he radiates away. At such high levels...

2 travelining in a straight line initial velocity is 14m/s, at a constant acceleration of 2.0m/s^2 to a velocity of 24 m/s a) how much time to reach velocity of 24m/s t= v-v0/a or 24-14/2= 5 seconds b) distance covered by car in this process? d=v0(t) + 1/2(at^2) or...

Homework Statement Compute the maximum amount of water vapor per unit volume that air can hold at the surface, where Ts = 288 K, and at a height of 10 km where T = 220 K. Express your answers in kg m-3. Homework Equations e_{s}=Ae^{\beta T} e=\rho _{v}R_{v}T The Attempt at a...

Solve this?? There are w cakes and n people. The cakes are distributed to people randomly. Find the expected number of cakes a 'i' person can receive. The distribution is: a) Bernoulli distribution b) Binomial distribution c) Poisson distribution d) Uniform distribution e)...

Homework Statement You are given vectors A= 5.1 { i } - 7.0 { j } and vec B= - 3.8 { i } + 7.3{j}. A third vector C lies in the xy-plane. Vector C is perpendicular to vector A and the scalar product of vec C with vec B is 16.0. Find the x -component and y-component of vector vec C Homework...

Homework Statement A chair-lift runs at constant speed. Each passenger starts from rest at the lower station, and is delivered to the upper station with the speed of the lift. The lift raises 30 passengers a minute, of average mass 75 kg. The top of the lift is 300 metres higher than the...

I am fairly certain I am doing it right, but I want to double check. Homework Statement "If you have a 25 denier string, what is its weight in pound-force per mile?" These aren't so much as equations, but conversions. Homework Equations 1 Denier = 1g per 9000m 1g = 0.0098066 N...

Homework Statement A water wheel rotates a generator producing power from vertically flowing water onto its blades. Height of water is 100m above blades. init vert velocity is 0. I have calc velocity at hitting wheel as 44.3m/s calc the mass of water hitting the wheel per second to create...

I need to know how much the water temperature will change in a PVC pipe. I have a 1.2m long PVC pipe filled to 1 meter of water. The inside diameter is 12 inches and the outside diameter is 13 inches. I have a plastic end cap on the bottom and the pipe stands up vertically. I keep it in a 20...

Say I have a device (Thermoelectric generator) that "generates power" at 4 watts, as per watt meter reading, is it producing 4 watts a second or 4 watts an hour. I say it is producing 4 watts a second but my brother in law says 4 watts an hour so the watt meter can tell the future. Please bear...

hi, thank you for taking the time to read my post, im looking at how to convert the force from a piston moving at approximately 1 meter per hour into electrical power via generator, any ideas appreciated the piston will be slow moving but generate an extremely large force, its a question...

Homework Statement You are playing a note that has a fundamental frequency of 428 Hz on a guitar string of length 56 cm. At the same time, your friend plays a fundamental note on an open organ pipe, and 6 beats per seconds are heard. The mass per unit length of the string is 2 g/m. Assume the...

Can C be measured in MeV?? If so is this per photon? Basically as the title states, can you measure C in MeV, i read ALICE was nearing Acceleration of C at 14 MeV (These numbers are what i can remember from a while ago). Then is that measure of 14 MeV for say a single atom, or does it apply...

Hello, My whole goal of going to college is to make myself as marketable as possible to employers. I'm a incoming freshmen and have to sign up for my courses. Due to taking several college courses while in high school I have reduced the number of credits for my BS down to 109. I'm going to...

How to calculate kinetic energy/ speed per particle (atom, ion, electron, molecule.. the AVERAGE kinetic energy stays the same, but the speed differs, as there are different masses.. ) at given temperature?

Homework Statement Calculate the average binding energy per nucleon in the deuterium nucleus. Homework Equations Average binding energy= total binding energy/mass number The Attempt at a Solution Would i first have to find the mass of the nucleus and then the difference in mass? My...

I understand that I don't "get" the whole HD video thing but regardless, what the HELL is up with video files with 60 fps? One needs an expensive computer to adequately display such a film and for what? Is there really some dumb *** who has tricked himself into thinking he can even SEE the...

Hello, I hope you can help me. I want to "alter" a sine wave. I would say "modulate", except that I was unsatisfied with the FM formula. Here's what I want, visualize this: 1) copy-n-paste an image of a sine wave into MS-Paint 2) select part of the image from wave top1-to-bottom1 3)...

Homework Statement The activity of a sample of (35/16)Sulfur with a t(1/2) of (7.55*10^6 s) is 3.52*10^5 decays per second. What is the mass of the sample? Homework Equations N=Noe^-lambda*t lambda=.693/(t1/2) No/DeltaT=lambda*N The Attempt at a Solution My attempt was to...

Time and relationships (or, "consciousness" per Martin Heidegger) In this forum we focus again and again on questions about “consciousness” – and I think there’s a deep reason why the meaning of this term tends to remain so unclear. Basically what we’re trying to understand is how our...

In an experiment, a ruler is connected to the table and some weights are bounded to one end of the ruler. The ruler is then flicked and the time taken per oscillation is measured. I have plotted a graph with the data I have collected, with the mass on the y-axis and time on x-axis. The graph...

Assuming you don't have to pay for a house/flat renting? I understand there is no single value, and a lot depends on the place, but I am looking for some average/order of magnitude...

Homework Statement The Earth is surrounded by an electric field, pointing inward at every point. Assume a magnitude of E = 167N/C near the surface. What is the net charge on the Earth? How many excess electrons per square meter on the Earth's surface does this correspond to? Homework...

So in this engineering course I do at my university called Statics, we often use a unit of lb per ft as a unit of force when calculating moments. However, I was just watching an episode of Big Bang Theory when Sheldon said something about a common mistake being when people use lb per ft as a...

I need to obtain the mass per unit length. Is it as simple as just mass / length?

In general, if I have a constellation of symbols, how can i calculate the energy por bit? I think I should calculate the area of figure which is formed linking external points in the space signal and divide it for the numer of bit compose the symbols. Right?

Homework Statement A sample of dry air has initial pressure p1 = 1000 hPa and temperature T1 = 300k. It undergoes a process that takes it to a new pressure p2 = 500 hPa with unchanged temperature T2 = T1. Compute the mechanical work per unit mass performed by the sample under the following...

I am just trying to understand exactly what luminosity per unit frequency is. I know that luminosity (L = 4PI(r2)(flux)) is amount of energy per unit time, but not sure what it means when it is also per unit frequency. The question has a cosmic source of 100 solar luminosity, all emitted...

Homework Statement A solution is prepared by dissolving 0.475g of (NH4)2SO4 in enough of distilled water and the solution is made up to 2.0 dm3 Calculate the ppm of NH4+ Homework Equations The Attempt at a Solution (NH4)2SO4 -----> 2NH4+ + SO42- 0.475/132 = 3.598...

I have to find the E field at all points on the z-axis for a ring of charge with radius = R. \lambda(\phi) = \lambda_0 cos(\phi) where 0 \leq \phi < 2 \pi I know how to do the problem when it is the charge per length is uniform but when I do the calculation for the non-uniform case I...

Homework Statement In a hydrogen atom, the electron in orbit around the proton feels an attractive force of about 8.18 × 10−8 N. If the radius of the orbit is 4.57 × 10−11 m, what is the frequency in revolutions per second? Answer in units of rev/s. Homework Equations Fc= mv^2/r (2...

Homework Statement Bacteria use swimming to seek out food. Imagine that the bacterium is in a region of low food concentration. For the bacterium to profit from swimming to a region with more food, it has to reach there before diffusion of food molecules makes the concentrations in the two...

Here is the 3 part question: Latitude and Longitude Discuss and explain the latitude and longitude measurements on the Earth. Explain what is meant by a great circle, a parallel and a meridian. Assume the Earth is a sphere with the equator circumference of 40, 075 km. (a) An airplane...

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...

I need some direction with respect to this problem please: Define the inner product on P4[x] over \Re as follows <f,g> = \int_{0}^{1}\f(x)g(x) dx let W be the subspace of P4[x] consisting of the poly. ) and all polynomials with degree 0, that is W =R Find a basis for...

I'm trying to figure out the realistic calorie burn for a person involved in a cardiovascular activity. Google helps little, because there are all sorts of wildly ranging numbers and 99% of them are uncited or second- or third-hand. I'd like a scientific source. Let's assume an untrained...

Please reply in layman terms. Thanks. Gross Domestic Product, GDP, is the amount of goods and services produced in a year, in a country. It is the market value of all final goods and services made within the borders of a country in a year. I think it's the financial value (in other words...

what is the best formula for elephants toothpaste not using yeast using potassium iodine and hydrogen-peroxide(30%) and of course soap. how much reactants would i need to fill let's say... 100m cubed (im not going to do that much but its easier to work with) * how long would the reaction take...

Hi, Please see the attached document. In a simple calculation, I am trying to add the cash flow per share of two companies. I think I am doing something wrong as I am not able to reconcile the results of this calculation to the actual results. Can you please take a look? Thanks, MG.

Maybe a stupid question, but anyway. The paper "Experimental Quantum Cryptography" by C. Bennettet al. discusses laser pulses of 0.1 expected photon per pulse. What does that mean physically? Is it that 90% of laser pulses are not pulses at all, containing no photons and thereby no energy? Or...

Hi, A cylinder is to be coated on a rotating lathe, with a coating rod moving by a mechanical robot in the X direction (back and forth). The cylinder is 300mm in length, 19mm in diameter. What is the distance traversed per revolution of a rotating cylinder, with the lathe rotating at 1200RPM...

Homework Statement What is the magnitude of the centripetal acceleration of a point on the circumference of a 0.32m radius bicycle wheel rotating at 22 rad/s ? Give your answer in metres per second squared Homework Equations To be honest I am stumped I have no idea The Attempt at...

Homework Statement Volumes of 1, 5, 10 and 15mL .0024M K2CrO4 are added to separate flasks and then filled with enough .25M NaNO3 to make 100mL of solution each. I'm asked to calculate the [CrO4^2-] per flask. I assume that all of the K2CrO4 will dissociate and, since there is only 1mol...

Homework Statement An electric-generator turbine spins at 3460.0 rpm. Friction is so small that it takes the turbine 14.9 min to coast to a stop. How many revolutions does it make while stopping? (Do not include a unit with your answer.) Homework Equations rev/min * 1min/60sec =...

Hi, I asked a question about a week ago -- and didn't receive a response, so I'm trying a perhaps easier question. :) About hour many hours per week should one expect to spend earning a Ph.D. in Mathematics? Thanks, David