Specific Definition and 1000 Threads

  1. S

    Specific heat and possibly latent heat too..

    Homework Statement 0.5kg of ice at 0 degrees celcius is mixed with 0.1kg of steam at 100 degrees celcius. what will be the final temperature? Homework Equations delta Q= m*c*delta T and at first i thought delta Q= m*Lf ,but then i changed my mind. . . The Attempt at a Solution...
  2. O

    Finding Distance Function with Increasing Outputs

    For determination of the distance from a certain point, a function should be used. Namely, the input values 'x' are from N (1,2,3,4,5...), and the corresponding outputs 'y' from R, but such that the sequence 'y' (relative to 'x') is increasing; $y(1)<y(2)<y(3)<y(4)<...$ \\ but to satisfy \\...
  3. M

    Help finding a specific RF chip

    The basic premises of what I am trying to do, is build a transmitter receiver circuit that has a signal strength identifier so I can calculate the distance between the transmitter and receiver. For example, if the chip is receiving 100% of signal strength (2mW) the distance equals 40 feet, and...
  4. T

    Specific Volume: Is It Intensive or Extensive Property?

    I have a query regarding Specific Volume, which is a property of a substance. I don't get why it is considered as an Intensive Property. It IS dependent on mass (SV = m/density) and hence I think it should be an Extensive Property. Could someone explain pl?
  5. radou

    Compactness of [0, 1] in a specific topology

    Homework Statement Let R have the topology consisting of all the sets A such that R\A is either countable or all of R. Is [0, 1] a compact subspace in this topology? The Attempt at a Solution If U covers R, if it consists of sets of type A such that R\A is finite, then [0, 1] is compact...
  6. M

    Calculating Nitrogen Specific Volume for Scientists

    I need some help in calculating the specific volume ( in cubic metres per kg) of Nitrogen at various temperature + pressures. Eg, at 100.73K and 817kPa. Can anyone please point me in the right direction ?
  7. D

    Specific heats relating to ideal gas properties?

    Partition separates two gases in a rigid well-insulated container. Q=0, W=0. State 1: Air: m=1kg P=500kPa T=350K CO_2: m=3kg P=200kPa T=450K Assume constant specific heats. Assume kinetic and potential energy changes are negligible. Assume the partition between the two gases...
  8. D

    Proving the Density of a Specific Set in Real Numbers

    Is there an easy way to prove that for any irrational \xi the set: \{x \in \mathbb{R}: x = p + q\xi, \ p, q \in \mathbb{Z}\} is dense in \mathbb{R}? I know a proof involving notions from measure theory of which I unfortunately know nothing about. Any help would be very appreciated.
  9. U

    Calculating Specific Volume of Water at 500 kPa and 20°C

    Homework Statement water at 500 kpa and 20 degrees CelsiusHomework Equations how do i find the specific volume?The Attempt at a Solution my charts only give me specific volume at the saturation points, but i know this is below any saturation point, so I've hit a road block
  10. U

    Physics A physics undergrad university with specific criteria for a SAM student

    hi, am new in this forum thing, from Malaysia, currently pursuing South Australian Matriculation, graduating in 2010. I would like to major in physics and later be a lecturer whilst conducting researches. Would prefer to study overseas. Which university or college would be suitable with the...
  11. D

    A couple specific Physics problem solving questions

    I'm in my first ever Physics class and have a few questions concerning skills involving solving Physics problems. I've been noticing that even though I get the right answers, my work getting there is a mess and unorganized. With that said, I have a hunch that won't fly in the upper level...
  12. N

    MATLAB Stoping a specific matlab function

    Hi all, I'm having some issues with Matlab. I'm running ode45 inside a function which is called repeatedly in a finite loop. As it is being called, Matlab is plotting and saving the data externally. Here's a quick pseudo-code func1 ( ) loop { data = func2 (variables) save...
  13. K

    Constant volume Specific heat and internal energy relationship in nonideal gas.

    Hi, 1. \color{blue}dq=dU+PdV so C_V = \left(\frac {\partial q}{\partial T}\right)_V= \left(\frac {\partial U}{\partial T}\right)_V leads to dU=C_{V}dT so \color{red}\left(\frac {\partial U}{\partial V}\right)_T = 0 meaning that internal energy of NONideal gas is a sole function of T? 2. As...
  14. A

    Angular momentum of hydrogen atom in specific energy level

    Homework Statement A hydrogen atom is in a state with energy -0.278 eV. Homework Equations L = nh' The Attempt at a Solution The answer book says to do E_n = (-13.6 eV)/n^2 but I can't find this equation in our book. Is the 13.6 a significant number or just a different number...
  15. R

    Why Can't I Solve This Limit Problem Without L'Hospital's Rule?

    Homework Statement [PLAIN]http://img545.imageshack.us/img545/5494/61141879.png The answer is 2, but I just can't figure out how to get to it. Homework Equations none The Attempt at a Solution Tried all methods taught in school but none works. Adding related expression...
  16. H

    Confusion regarding Thermodynamics - Molar Specific Heats for Gases

    Homework Statement From Giancoli's UC Berkeley edition Physics for Engineers and Scientists: A 2.00 mole sample of N2 (nitrogen) gas at 0 degrees C is heating to 150 degrees C at constant pressure (1.00 atm). Determine the heat added to it.Homework Equations Variables in equations: V = volume...
  17. R

    What Is the Specific Gravity of a Cube Weighing 0.54kg with 5cm Sides?

    1. A Cube of lengths 5cm each. The cube weighs .54kg. What is its specific weight? 2. Answers: A)6 g cm3 B)3 g cm3 C) 2.5 g cm3 D) 2 g cm3 3. 5x5x5 = 125cm3 540g/125= 4.32 g cm3 which is none of the above. Could someone verify that I'm correct before I make an idiot of myself when...
  18. JJBladester

    Find position and velocity at specific time

    Homework Statement The acceleration of point A is a = -5.4sin(kt) ft/s2. k = 3 rad/s. When t = 0, x = 0 and v = 1.8 ft/s. Determine the position and velocity of point A when t = 0.5s Answers: x = 0.598 ft v = 0.1273 ft/s Homework Equations...
  19. T

    Can a Sinewave Be Generated from an Oval Phasor?

    I am not an expert in math, but as an electronics tech we use sinewaves all the time. I understand how it is derived from a circle well enough ( a phasor rotating about a circle). And that makes sense as that is how electricity can be generated due to the orientation of the generator...
  20. M

    What determines the specific heat capacity of a given substance?

    I'm fascinated with physics and probably know at least the nature of any effect or object in classical physics, but um... I have never in any textbook or article seen mention of what determines the specific heat capacity of a given substance. Which is kinda peculiar and confusing at the same...
  21. E

    The number of ways to express a specific summation

    Hello all, I have been thinking about a particular mathematical question (that I've made up) and I haven't been able to reach a solution yet.. I want to find the rule for the function F(x,y) which gives the number of different "ways" that the integer x can be expressed as the summation of...
  22. G

    Specific Heat Capacity and Specific Latent Heat

    Hi Everyone :smile: I have to create an experiment for my assignment in Physics. I've chosen to do something about Specific Heat Capacity. A boy in my class is also doing SHC so I wanted to make mine a little different from his. I've just recently joined physics (never done it before)...
  23. D

    What is the meaning of the sigma notation in this matrix A?

    I've been clawing at my mind for a while regarding this, I pray somebody can help me. I was implementing a method from a computer science paper when I came across this: [PLAIN]http://www.mattkent.eu/challenge.png Bearing in mind that x is a vector, epsilon is a vector of integers (and...
  24. A

    Orientating objects to align with a specific axis

    Hi!, I'm well into the world of computer graphics. Love to say it was great but well, it isn't. I would like to know how I can take any object and have it orientate so its centre aligns perfectly with any arbitrary axis. Think of a cylinder at the origin pointing down the x-axis. Well I...
  25. T

    HELP Specific Homework Problem, Particles and Waves

    I have read the entire chapter in my book and have searched the internet and I still have no idea where to even begin. HELP! 4. a.) Explain the significance of a probability of 1.0 and of a probability of 0.0. b.) Calculate the probability for an event to occur if 420 events have...
  26. S

    Need school advice for specific area of study.

    Hi Physics Forums! I'm brand new here, My name is Randy. I recently decided not to re-up in the army and instead attend collage full time. I'm currently a student at Devry, But I've decided that physics is more than a lifelong hobby, it's something I could do everyday and be a happy and...
  27. T

    Where can I find the actual velocity and position of earth at a specific time?

    I would like to know the three dimensional velocity and position of the Earth with respect to the solar system center of mass at a few specific times. Similar data for the planet mercury and the moon would also be very helpful. Is there a web cite that where I could find the data...
  28. T

    Using the specific heat of any substance

    Ques 1) In determining and then using the specific heat of any substance:- For solids and liquids, we usually assume that the sample is under constant pressure during the transfer, or at constant volume while the heat is absorbed. Then is it possible that the thermal expansion of the sample can...
  29. I

    Can Internal Vibrations Affect Temperature and Specific Heat?

    In thinking about specific heat, I have been unable to resolve a particular issue. If molecules in a substance are bumped and move faster, then they will measue to be at a temperature proportional to the speed they are moving which is a consequence of how hard on average they were hit(heat...
  30. S

    Equivalent Current Through Specific Resistor

    Homework Statement http://farm5.static.flickr.com/4117/4775531139_8d4dd954f5_b.jpg Homework Equations I = V/R E = I1R2 = I2R2 =I3R3 The Attempt at a Solution I got 5.22 ohms for part (a), but I'm not sure how to go about calculating the amps through a specific resistor.
  31. DocZaius

    Would a specific change in earth's rate of precession mean no seasons?

    This is not a homework question. This is the result of trying to think of a way to remove seasons. Imagine a case where the Earth's axial precession had a period of exactly one year (instead of about 26,000 years) and that such a precession was counter clockwise (matching the direction of the...
  32. Y

    Question about determing specific heat capacity using waterfall.

    Homework Statement The temperature at the top of a popular waterfall is 22.0 degrees celcius. The temperature at its base, 210 m lower, is 22.5 degrees celcius. 1)Caluclate the specific heat capacity of the water. 2) If the waterfall was twice as tall, determine by how much the water...
  33. N

    Thermal Conductivity, Specific Heat & Human Perception: A Physics Q

    This question pertains to the (non)relationship between thermal conductivity, specific heat, human perception and thermosensors. Here goes: Let's say I place four thermosensors on my body. Then, on top of these thermosensors I place four different items (A, B, C, and D). All four items start...
  34. P

    Einstein's formula for specific heat

    I'm working through a derivation of Einstein's formula for specific heat and I'm stuck. So far I've been working off Planck's assumption of quantised energy E=n\hbar\omega and the energy probability P(E)= e^{\frac{-E}{k_b T}} , using the fact that the mean expectation energy is \langle E...
  35. P

    Einstein's formula for specific heat

    I'm working through a derivation of Einstein's formula for specific heat and I'm stuck. So far I've been working off Planck's assumption of quantised energy E=n\hbar\omega and the energy probability P(E)= e^{\frac{-E}{k_b T}} , using the fact that the mean expectation energy is \langle E...
  36. M

    Specific Gravity and Pressure in Flowing Pipe

    Homework Statement The following question is from ExamKrackers Physics [an MCAT prep book]. An ideal fluid with specific gravity of 1.0 is passed through a pipe. Along the length of the pipe shown above are attached 3 vertical pipes which are sealed off as shown above. If now a different...
  37. G

    How to calculate voltage at a specific resistor

    Homework Statement How would you calculate the voltage at a specific resistor given that it's a parallel circuit.
  38. C

    Molar Specific Heat: Difference Between CV & CP

    1. Homework Statement What si the difference between the molar specific heat at constant volume and at constant pressure? Homework Equations The Attempt at a Solution
  39. A

    Finding a Linear Transformation with specific domail and range

    Hey, i have an assignment in MATLAB class which is Let L be a linear transformation such that L(1)=(2 -1)' L(1-x)=(1 0)' L(1+x^2)=(1 1)' L(1+x^3)=(1 2)' Determine a matrix in domain such that with the canonical in range, the matrix that represents L has two null columns. I don't know...
  40. P

    How Do You Calculate Specific Heat Capacity and Latent Heat of Fusion for Lead?

    Homework Statement 3.00 kg of molten lead is allowed to cool until is has solidified. It is found that the temperature of the lead falls from 605 K to 600 K in 10 s, remains constant at 600K for 300 s, and then falls to 595 K in a further 8.4 s. Assuming that the loss of heat energy remains...
  41. S

    Molar specific heat capacities for gases

    For an isochoric process, dV = 0 therefore dW=0 So from 1st of Thermodynamics, dQ = dU + 0 or, n*Cp*dT = n*Cv*dT (Cp and Cv denote molar heat capacities of the gas at const pressure and volume resp.) therefore we get Cp = Cv .(how can this be possible once we know Cp - Cv = R ?)
  42. P

    Confused about battery's specific power and energy

    Hello there, I am so confused about the term battery specific energy (in Wh/kg) and specific power (in W/kg) Actually, I know what it means by power and energy, of course P = E/t But looking at the text, which quotes like "Ni-Cd batteries have high specific energy (than Ld-acid) but...
  43. C

    Variation of specific heat with temperature

    how does specific heat of gases vary with temperature? is there an equation to describe it?
  44. T

    Experiment to find specific heat of a liquid

    Homework Statement Determine the specific heat of a liquid USING a resistance heater. Exact problem - Design an experiment complete with instrumentation to determine the specific heats of a liquid using a resistance heater. Discuss how experiment will be conducted, what measurements need to...
  45. Rasalhague

    Eccentricity and specific mechanical energy

    Bate, Mueller, White: Fundamentals of Astrodynamics (Dover 1971), p. 29, equation 1.6-4 for the eccentricity of a satellite's orbit: e=\sqrt{1+\frac{2\mathcal{E}h^2}{\mu^2}} e \text{, eccentricity} \mathcal{E} \text{, specific mechanical energy} h \text{, magnitude of specific...
  46. C

    What Are the Cp and Cv Values for Petrol and Air?

    what are the Cp and Cv values of petrol and air?
  47. P

    Specific latent heat and heat capacity

    Homework Statement 0.1kg of ice was added to a lemonade of mass 330g at an initial temperature of 28 degree celcius and it completely melted. Considering only the lemonade and ice cubes, calculate the final temperature of the lemonade. Given: specific latent heat of fusion of ice= 336000...
  48. S

    Specific heat capacity and latent heat.

    a 210 heater is places in 2 kg of water. What temperature rise is produced if the heater is switched on for 200 seconds? I need your help please.
  49. U

    Physics refraction and Specific heat capacity problem

    I am a IGCSE student! Ok so in the physics w08 qp ( http://www.xtremepapers.net/CIE/Cambridge%20IGCSE/0625%20-%20Physics/0625_w08_qp_03.pdf ) Qestion 5 c Using a 40 W heater, 16.3 g of ice is melted in 2.0 minutes. The heater is then switched off. In a further 2.0 minutes, 2.1 g of ice...
  50. I

    Possible combination of specific size

    I have list of numbers like 3100002 11200002 11200011 12010011 12010020 20110002 20110101 21001020 21001110 30000300 100300020 . . . . I need all possible combinations of specific size depending on some conditions. size of combination can vary from 3 to 25. I am doing it...
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