Volume Definition and 1000 Threads

Homework Statement Daniel Schroeder, introduction to thermal physics problem 1.36 (page 26): "In the course of pumping up a bicycle tire, a liter of air at atmospheric pressure is compressed adiabatically to a pressure of 7 atm. (Air is mostly diatomic nitrogen and oxygen.) a) What is the...

In the constant volume gas thermometer, T (°c)=[P(T)-P(f)]×100/[P(b)-P(f)] (P(T) means gas pressure at T°c P(b) and P(f) for the water's boiling point and freezing point) Is it right?

Homework Statement A sphere of radius R has a volume charge distribution ##\rho(r)## given by: ##\rho(r)= \rho_0 \left( \frac{r}{R_0} \right) \ \ for \ 0 <r<R## ##\rho(r)=0 \ \ elsewhere## Where ##\rho_0## is a constant. Use Gauss's law to find E field outside the sphere. Homework Equations...

Homework Statement Flat space-time in polar coordinate is considered. The line element is ds2= -dt2+dr2+r2(dθ2+sin2θdΦ2) The actual answers are given below, but I can't come up to them. Need urgent help. Homework Equations dA = √g11g22 dx1 dx2 dV = √g11g22g33 dx1 dx2dx3 The Attempt at a...

My first question is, what is a diagonal metric? Secondly while calculating the area and volume of a diagonal metric, why do we calculate it like dA = √g11g22 dx1dx2 instead of dA = g1g2dx1dx2 ?

Homework Statement So I have a problem/question were tanks are filled with water and its specific weight is 9.45 kN/m^3. They also give you a range of volumes of different tanks. The problem then asks for the plot of added weight (kN) due to the liquid for the given range of the different tank...

So I have a problem/question were tanks are filled with water and its specific weight is 9.45 kN/m^3. They also give you a range of volumes of different tanks. The problem then asks for the added weight (kN) due to the liquid for the given range of the different tank sizes (diameter). My...

Homework Statement 2 moles of water undergoes electrolysis at 10A. What is the total volume of the system after 1hr? Homework Equations 4 H+(aq) + 4e−→ 2H2(g) 2 H2O(l) → O2(g) + 4 H+(aq) + 4e− Faraday's Law of Electrolysis Q = n(e-) x F F = 96500C The Attempt at a Solution Initial volume...

(note I am designing this question myself, in order to understand this phenomenon by example) Homework Statement Find the total radiative power emitted within a 0.1 m2 semi-transparent medium, having an absorption coefficient of 5 m-1 over all spectra, and a temperature of 1000 K. Note that...

Given any tetraedron, I want to calculate the volume V in function of the areas of the surfaces of the solid. I found this pdf that explain this: http://daylateanddollarshort.com/mathdocs/Heron-like-Results-for-Tetrahedral-Volume.pdf But, o pdf says that beyond of the 4 faces (X, Y, Z, W) is...

See the image that I uploaded... I want to write the surface S (bounded by edges u, v and w) in terms of x, y and z, u, v and w and A, B and C. And I got it! See: S(A,B,C) = \sqrt{A^2+B^2+C^2} S(x,y,z) = \sqrt{\frac{1}{4}( (yz)^2 + (zx)^2 + (xy)^2 )} S(u,v,w) =...

Taken from http://dao.mit.edu/8.231/BZandRL.pdf BCC In real space, it has a simple cubic lattice with one basis in the centre. Total number of atoms per unit cell = 2. Volume of primitive unit cell is then ##\frac{1}{2}a^3##. In reciprocal space, BCC becomes an FCC structure. It has a simple...

I'm not getting the right answer... why?

In some questions, I've noticed that some questions which relate to equations that involve mass (Kg) and I am given a volume. e.g http://gyazo.com/169d40e27c5a14508724cb574635aca8 Know I that Δu=mCΔT, and I know that Δu=400w x t = m x 4200 x 60 and solve for t, but do I assumption that 1Kg = 1 L ?

A spherical shell has an outside radius of 2.75 cm and an inside radius of a. The shell wall has uniform thickness and is made of a material with density 4.59 g/cm3. The space inside the shell is filled with a liquid having a density of 1.00 g/cm3. (a) Find the mass m of the sphere, including...

The required Formulas are: Area of circle = Pi (r)^2 Volume of Cone = 1/3 Pi (r)^2 h Here is my try: I know the smaller cone and bigger ones are congurent, so 50/25 = 15/h h=7.5, but the answer is incorrect. Please help

The density of an object equals its mass divided by its volume. The mass of Earth is 6x10e+24 and its radius is 4000 miles (1.61km = 1mile). What is the density of the Earth in kg/m^3?V=4/3pi(r)^3. D=M/VConverting 4000 to Km, I get 6400. After plugging it into the Volume equation, I end up with...

Homework Statement The problem is asking to find the volume of this pulley Formulas that is in the chapter. Area = r^2*θ/(2) Where θ is in radians Homework Equations I drew the drawing in solid works and got the volume to come out to 6.27 cubic inch. But I am not sure if this is the correct...

I am trying to work out a formula for the approximate calculation of the lung capacity of a racehorse. http://performancegenetics.com/wp-content/uploads/2015/05/Horse.jpg I take three physical dimensions on the horse. 1) The measurement of the girth (which is the perimeter of an ellipse)...

The question seems to be of quite low level yet many of teachers i found are unable to explain me the exact concept that what is mass density and volume.Yeah i know the formula d=m/v also v=a^3... Please explain what practically & exactly they are and how both formula has came exactly. Please...

What if the Friedmann equation told how the (square of) fractional growth rate of spatial volume relates to the energy density, instead of describing how the (square of) fractional growth rate of spatial distance relates to energy density? Just two slightly different ways of describing the...

Find the volume laying inside x^2 + y^2 + z^2 =2z and inside z^2 = x^2 + y^2. This is a problem my professor made, so I have no way of checking my answer. What I did first was completed the square for the sphere and got x^2 + y^2 + (z-1)^2 = 1, which is a sphere of radius one shifted above the...

Hi. I'm trying to write some anatomical systems for a game I'm coding, and i need some good data to work from. Our game is about dogs, not humans, but i figure a human will be close enough What I'd really like is a case study of a specific organism, and i'd like to know the compositions, by...

Hey all 1. Two speakers emit sound in phase with the frequency of 13.2 kHz, the sound from the loudspeakers directed at points A , B and C. Rank the volume of the three points with the weakest first. speed of sound 340m/s 2. 3. I think I need to use Pythagoras says to calculate the path...

Homework Statement Gas occupies 2m^3 at a pressure of 100kPa. What is the pressure when the volume is 1.5m^3 and the temprature is unchanged? Homework Equations p=nRT/V The Attempt at a Solution As a logic conclusion i took 1.5/2x100 and got 75 but 175 is not the answer.. The answer is...

Homework Statement There is charge placed in a volume of a sphere, whose density changes by expression ρ(r)=ρ0a/r for 0<r≤a and ρ(0)=0. Where a and ρ0 are known variables , and r is a distance from the origin. Determine the potential of the point A(0,0,0) with regard to reference point at...

Hi all, I have the next dude: To utilize the Huygens principle at the boundary of a volume, do we need to know precisely material properties inside the volume? Thanks!

Homework Statement Homework Equations PV = nRTThe Attempt at a Solution n = 5.3 moles R = 8.31 J/(mol K) T = 273 K now, with P, do we use 1 atm or 1.013 x 105 i'll go with the latter, and the answer comes out to be 0.119 liters , does this sound correct?

First, two definitions: let ## \varrho (M)## be the probability density of macro states ##M ## (which correspond to a subgroup of the phase space) and ## \mathrm{d} \Gamma ## be the volume element of a phase space. In my lecture notes, the derivation for continuity equation of probability...

Homework Statement Using a suitable Jacobian, evaluate the volume bounded by the surface ##z = 2 +x^2##, the cylinder ##x^2 + y^2 = a^2## (where ##a## is a constant), and the ##x-y## plane. Homework Equations ##x = r cos{\theta} ## ##y = r sin{\theta} ## The Attempt at a Solution I...

Hello PF! I have some questions regarding the accumulation term for the energy balance on a variable volume system. Suppose we have a tank storing a liquid substance. The tank has a moving boundary at the top, which can expand unlimitedly. The system has a mass input \dot{m}_1 and mass output...

Homework Statement The circumference of a sphere was measured to be 90 cm with a possible error of 0.5 cm. Use differentials to estimate the maximum error in the calculated volume. Homework Equations Volume of sphere: V=4/3πR3 Circumference of Sphere: C=2πR ΔC = 0.5 cm The Attempt at a...

Homework Statement [FONT=Arial]An aluminium container (cylinder) is filled with glycerine. Glycerine has a volume expansion coefficient of 4.85 × 10^-4 (°C)-1. Aluminium has a linear expansion coefficient of 2.40 x 10^-5 (°C)-1. At a temperature of 20.00°C the scale on the side of the...

I may have misinterpreted this but today in calculus (AB) we were forming solids from 2 dimensional equations. One of the methods involved taking an integral of an area equation to solve for a solids volume. I got very excited as I often have difficulty remembering volume equations but am...

This is the general equation for the packing parameter to find out what shape the lipids arrange into: And this is what we have been given in class: http://i.imgur.com/iGsbXHi.jpg I'm struggling with the surfactant tail volume, v term. I understand the a is the optimal surface area...

Homework Statement An iron casting weighs 300 N in air and 200 N in water. What is the volume of cavities in the casting, if the density of iron is 7800 kg/m3 ? Homework Equations d = m/V Fg = mg The Attempt at a Solution I was not sure in the slightest of how to solve this problem. So I...

Homework Statement there is an expandable container with 1m3 of hydrogen and 1/2 m3of oxygen at stp. the gas is ignited.what is th final volume if there is no heàt lost and the pressure outside the container is 1atm? assume complete combustion Homework Equations other than the ideal gas...

Homework Statement Find the volume of the solid. Under the paraboloid z = x^2 + y^2 and above the region bounded by y = x^2 and x = y^2 Well, those curves only intersects in the xy-plane at (0,0) and (1,1), and in the first Quadrant, and in that first Quadrant y = sqrt(x), and over that...

Homework Statement 2. Homework Equations n/a The Attempt at a Solution [/B]1) Whenever I need to find the volume between two surfaces, the integrand is simply the difference (subtraction) of the two equations? In the solution guide above, it is clear that they subtracted the two...

Use the method of cylindrical shells to find the volume of the solid obtained by rotating the region bounded by the given curves about the x axis. $x=1+{y}^{2}$, $x=0$, $y-1$, $y=2$ https://www.physicsforums.com/attachments/4237 The answer is $\frac{21\pi}{2}$ but I couldn't get it using...

Suppose someone gives you a rectangular sheet of length a and width b (so b ≤ a). You make a topless box by cutting out a square with length x out of each corner and folding up the sides. How should you cut the sheet so as to maximize the volume of your box?

Its given in my textbook that equivalence of gas = (volume of gas) / (Volume of 1 eq. gas at NTP) How do i calculate volume occupied by 1 equivalent of gas? Example: What would be the volume occupied by 1 eq. of CO2 (Its given 11.2l in my book) Is there a formula for this?

Homework Statement In a particular region of the Earth's atmosphere, the electric field above the Earth's surface has been measured to be 148 N/C downward at an altitude of 260 m and 165 N/C downward at an altitude of 410 m. Calculate the volume charge density of the atmosphere, assuming it to...

Hello everyone, I have a discrete class D project that I need help with but since I'm not an analog guy I got a problem. So far I got everything set up and the discrete class D works perfectly. But only at maximum of 6 volts otherwise the Transistor M3 gets really hot and burned, how do I solve...

Hello everyone, I just need some help understanding some thermodynamics. So I have 0.25 kg of helium which is compressed from an initial state in a polytropic process with n = 1.3. So its given the change in volume and the initial pressure. I need to find the change in internal energy. I am...

This is probably an elementary question, but I stumbled upon it while thinking about total differentials. One of their many applications is calculating the error in a volume, for example, given uncertainties in its dimensions. I'm not in the mood to tackle a 3D problem, so let's revert to a 2D...

Hi all, I need help finding a formula to find the volume of a solid that has a fixed width and depth but 4 different heights. To see what I mean, please take a look at a sketch I drew below. Thanks.

Find the density

Homework Statement Just want to check that I've used the correct method for this thermodynamics question I've been set. Any clarification would be greatly appreciated. So I have 0.5kg of gas held in a rigid container of volume 0.25m^3 at a temperature of 20°C. 20kJ of heat energy is required...

Hi evryone, the system i am working on, is composed of two relatied non-linear equations that I discretised using finite volume method with fully implicit scheme, the difficulty is that the two unknonw appear in both equations and i don't know how to solve it. Any propositions? Thank you.