Capacity Definition and 639 Threads

I have having dificulty in determining the torsional capacity of a square HSS section. I am designing a shaft for 9.5 cubic yard mixer powered by a 80hp drive at 6 rpm output. I have calculated the applied torque to be 70,000 ft-lbs (95 kNm). I would like to determine the size of HSS...

Homework Statement Have to do a write up of an experiment on specific heat capacity of metals. Tested 50g of nickel and lead, each heated to 90C and then put into 50g of water and measuring the change in its temperature. Found that lead has a lower specific heat capacity. Homework Equations...

1. Homework Statement : Taking Earth to be a spherical conductor of diameter 12.8x10^3 km.its capacity will be? 3. The Attempt at a Solution : if Earth is to be taken as a conductor than i think following formula shall be used C=Aeo/d where A=pie r^2 but how i'll calculate...

hi everyone, in thermodynamics, when we calculate the heat capacity in constant volume, we assume Cv=dQ/dT.. well, but at isothermal condition suddenly they came up with Cv=dU/dT... so i am getting stuck with this concept how they replace dQ with dU? i know U= internal energy is only a...

1. How do I draw a diagram to demonstrate why motor oil has a higher specific heat capacity than water?

Given that heat capacity is a ratio of change of energy over change of temperature, while entropy is a change of energy over absolute temperature... I was wondering if there is any basis for the idea that energy will tend to flow from media having low heat capacity to media having high heat...

Newton's Law of Cooling basically states (I believe): TObj = (TInital-TEnv)ekt + TEnv where k is a property of the material. In the equation: Q=mCΔT Specific heat capacity, C, is also a material property. So here's my question: Is there a relation between Newton's Law's k and the...

Just a quick question of something I found in my textbook but can't get how they produced it. C_p =(∂Q/∂T)_p that is the definition of heat capacity at a constant pressure p. Q is heat and T is temperature. This equation is fine and I know how to derive it. Now it is the next line which...

Hello everyone. I indeed like to understand the things I am learning, and for the love of me, I cannot understand why, according to the formula, capacity of a condenser in a circuit consisted of said condenser and a power source is inversely proportional to the power source's voltage. Could you...

Below 20K, The specific heat capacity c of silver varies with temperature according to the equationc/\text{J /kg /K} = 1.5x10^{-4}(T/K)^3 + 6.0x10^{-3} T/K. If a small silver sphere of diameter 4am and at 20K is placed in 25g of liquid helium at 4K, what fraction of the liquid will evaporate...

I know how to do heat capacity problems but i am unsure of how to do them when two materials are combined together. Here is the question. Any help would be great, thanks. A 5 kg pieces of low carbon steel at room temperature 25°C is placed into contact with a 300g piece of polyethylene at 180°C...

Homework Statement 0.2g of a radium salt was separated from a ton of uranium ore. The radioactive radium nuclide Ra-226 decays by alpha-particle emission with a half-life of 1600 years. 1 year = 3.16x107s. The curie is defined as the number of disintegrations per second from 1.0g of Ra...

Homework Statement The temperature of one mole of ideal gas is 360K. The gas is allowed to expand adiabatically to the double volume. Then it is compressed isothermally to original volume. The specified amount of heat is measured at 1304J. Determine C_p / C_v, and specify the type of ideal gas...

Throughout my time doing physics I have noticed that ice has a lower specific heat capacity than water. I don't understand why. To me it seems that the bonds between water molecules in a solid are stronger and hence require a greater deal of thermal energy to break. Hence, the PE of the...

When we deal with heat capacity or specific heat capacity Q=mc(delta temperature) why don't we take into consideration about the expansion of the thing? Since expansion (should) increase the potential energy of the item since potential energy is the bond strength which is related to the particle...

I am doing my revision and noticed that metals all have a molar heat capacity ~25 J/mol/K = 3R. Ionic solids such as NaCl and CaF2 however have different molar heat capacities. (~51 and 72 respectively) Why is this? there is no explination that my lecturer gave and I can't find it online but...

I completed high school 9 years ago... please bare with me :) My problem is with how they calculate the actual answer - this is from an example problem in my textbook. Homework Statement A calorimeter cup is made from 0.15kg of Alu and contains 0.20 kg of water. Initially the water and...

Homework Statement http://www.physics.ox.ac.uk/olympiad/Downloads/PastPapers/BPhO_PC_2006_QP.pdf Q15b Answers: http://www.physics.ox.ac.uk/olympiad/Downloads/PastPapers/BPhO_PC_2006_MS.pdf I am confused on how the answer is reached, specifically how the formula energy...

I am quite confused by this, because I have not yet found a compound that has a higher one. My understanding is that specific heat capacity of a molecule is based on a combination of the number of degrees of freedom the molecule has and the number of vibrational modes. As for the second factor...

At what phase is the heat capacity the greatest? Is it when the substance is a solid, liquid or gas? Please also explain why. I believe that the heat capacity is the greatest when the subastance is a solid.

Homework Statement A saucepan of thermal capacity 500J/degC contains 5kg water at 20 degrees celcius. How much energy is required to raise the temperature of the saucepan and water: a) to 60 degrees b) by 60 degreesHomework Equations Q = mcΔt mcΔt = mcΔt The Attempt at a Solution First I just...

A bath contains 100kg of water at 60C. Hot and cold taps are then turned on to deliver 20kg per minute each at temperatures of 70C and 10C respectively. How long will it be before the temperature in the bath has dropped to 45C? Assume complete mixing of the water and ignore heat losses. I've...

Homework Statement A cube of gold is heated to a temperature of 94.2 degrees celsius, and then submerged in 31.3 mL of water at an initial temperature of 28.7 degrees celsius. If the final temperature of the water is 45.6 degrees celsius, calculate the volume of the cube of gold (s=0.130...

Homework Statement Using the viral theorem, the heat capacity of a star is given as C=-3*k/2. Using this, I need to calculate the entropy of a star in terms of the average temperature T, then in terms of U (total energy). Homework Equations dS=C*dT/T The Attempt at a Solution To...

Homework Statement there is a bath of 160L of water at 41oc (shc 4000). A rock of 15kg is dropped into the bath at 250oc with shc of 2000 What temperature does the water end up at? Homework Equations Q=cmT The Attempt at a Solution Very sorry but I don't have a clue. Not...

Hi there, I am not an engineer but i do have scientific background. It is just a long time since i did any calculations! I am trying to design myself a new way of melting barrels of honey. I have 200L, 300kg barrels of crystalized honey that I need to melt. One method I envisage is to make an...

Homework Statement 215 cm3 of hot tea at 95°C are poured into a very thin paper cup with 40 g of crushed ice at 0°C. Calculate the final temperature of the "ice tea". (Hint: think about two processes: melting the ice into liquid and, maybe, warming the liquid.) Homework Equations 0 =...

does anybody have these numbers? it could be manufacturing SECTOR in $ of output. not looking for numbers of people employed in manufacturing or number of companies small and large. i think capacity is best. Have A Nice Day!

Homework Statement Part a. A 500 W kettle contains 300g of water at 20°C. Calculate the time it would take to raise the temperature of the water to boiling point. Part b. The kettle is allowed to boil for 2 minutes. Calculate the mass of water that would remain in the kettle. State any...

What is the the relationship between the specific heat capacity and power (e/t) required to raise the objects temperature? Of course the energy required increases, but does the time it takes change also?

I have a problem with heat capacity of different materials. i know that heat capacity is the mount of energy needed in order to rise the temperature of a material by 1 degree, but i also know that different amount of energy is needed to rise the temperature from 0 to 1 degree and different...

You warm 1.00 kg of water at a constant volume of 1.00 L from 20.0 degrees C to 30.0 degrees C in a kettle. For the same amount of heat, how many kilo grams of 20.0 degree C air would you be able to warm to 30.0 degree C? What volume would this air occupy at 20.0 degrees C and a pressure of 1.00...

I am doing a zainy experiment at home. I need to devise a way of applying a cooling intensity factor (CIF) of around 70 mW/cm2. I need to cool material that is roughly 30 degrees Celsius down to around 2 degrees Celsius. The cooling has to last for a period of one hour or more. The surface...

What are the Debye model`s assumptions for heat capacity or density of states? According to the einstein model we assume that N oscillators of the same frequency [ω][/o] and in one dimention. In three dimention N is replaced by 3N, there being three modes per oscillator.

Can the specific heat capacity be negative? Is there any substance for which i have to add heat to decrease its temperature? By the way,why specific heat capacity has the word "capacity" in it? Is there any physical significance to it or it is simply traditional(historical)?

How can i determine Specific heat capacity of Water cpv if i know all variables If i use this equation: [(mi1 + mi2 +mv)cpv + mg*cpg]dT/dt = H mi1 = mass 1 dT/dt = 0.05 cpg = 890 J/(kg*K) mi2 = mass 2 mv = mass 3 H = 300 W masses are arbitrary numbers Its cpv that...

Homework Statement cp=cv+TV?^2/? Homework Equations cp=T/N(\partialS/\partialT)p The Attempt at a Solution I have the equation, just not sure how to apply it? Any help would be appreciated

Homework Statement a 0.20kg lead shot is heated to 90 degrees celsius and dropped into an ideal calorimeter containing 0.50kg of water initially at 20 degrees celsius. What is the final equilibrium temperature of the lead shot? The specific heat capacity of lead is 128 Joules/(kg degrees...

Homework Statement The question is presented as picture. Homework Equations What is the expression of this 'heat capacity C'? The x-process is isothermal then C=nCΔT=0? Please give me some ideas. The Attempt at a Solution set V1=V2, V3=V4, T1=T4, T2=T3, p1+p0=p2, p3-p0=p4...

Homework Statement An unknown metal with C=3.6 Mass=150g Temp=160c is added to copper container(85g) filled with water(105g) both with an initial temp of 20c I have to find the final temp of water,container and metal Homework Equations none given but I assume it will be E=Cm(t1-t2)...

Homework Statement Heating a .8 kg disk of iron from 20 C to 400 C, but the specific heat capacity changes from 456 at 20 C, to 615 at 400 C. It hints that I'm supposed to find the average to solve the equation. Homework Equations E = mC(dT) The Attempt at a Solution I have a...

Homework Statement When a car brakes, an amount of thermal energy equal to 112500J is generated in the brake drums. If the mass of the brake drums is 28 kg and their specific heat capacity is 460.5 Jkg^-1K^-1? A piece of iron of mass 200g and temperature 300°C is dropped into 1.00kg of water...

Hello, I want to show: C_p - C_v = -T \big( \frac {\partial V}{\partial p} \big)_{T,n} \big( \frac {\partial p}{\partial T} \big)_{V,n}^2 I started by doing this: C_p - C_v= \big( \frac {\partial H}{\partial T} \big)_{p,N} - \big( \frac {\partial U}{\partial T} \big)_{V,n}...

Hello All. I'm trying to evaluate a design based on first principles. I have 2 trusses made from RHS (simple A frame) between which I wish to tech-screw a sheet of 2.9 mm galvanised sheet. Loading will primarily be from material (i.e. soil to a max depth of 400 mm) being placed on the...

I have a cheap oscilloscope that is rated for 10V input. I want to measure the quality of the output of my power supply due to a belief the DC filtering circuit isn't working well and producing harmonics in the signal (ripples). The output voltage is at a higher voltage coming out of a...

Homework Statement An ice cube of mass 40g is transferred directly from the freezer where it is at -8 CELSIUS to a cup containing 120g of water at 95 degrees CELSIUS. Calculate the final temperature of water. Ignore any heat transfer to the cup or its surroundings Homework Equations tf = ti +...

Homework Statement A mixture is made by adding 75g of an unknown liquid at a temperature of 25 degrees Celsius to 60g of water at a temperature of 90 degrees Celsius. The final temperature f the mixture is 65 degrees Celsius. Calculate the specific heat capacity of the liquid. What is the...

Homework Statement what is the different in term of definition between Heat capacity and Specific heat capacity ? Homework Equations Q=mΔTC →C=Q/mΔT The Attempt at a Solution Specific heat capacity is the amount needed per unit mass of material so is a number independent of the...

Homework Statement Atoms of the inert gas Krypton are adsorbed onto a smooth solid surface at 90K. They can move freely over the surface but they cannot leave it. For a sample with total surface area 2.5 m^2, and a surface density 3 nm-2, what is the heat capacity of the krypton? Homework...

Homework Statement "Derive a more accurate approximation for the heat capacity at high temperatures, by keeping terms through x^{3} in the expansions of the exponentials and then carefully expanding the denominator and multiplying everything out. Throw away terms that will be smaller than...