Final Definition and 1000 Threads

  1. D

    Final repulsed velocity of two different charged masses

    1. Two small metal spheres with masses 2.0g and 4.0g are tied together by a 5cm long massless string and are at rest on a frictionless table. Each sphere has a (mue)c charge. The string is cut, what are the velocities of the sphere when they are far apart I know two conservative qualities are...
  2. Z

    Understanding Final Value Theorem in Laplace Transform: Tips & Examples

    http://fourier.eng.hmc.edu/e102/lectures/Laplace_Transform/node17.html On that page about final value theorem, it says that; However at the bottom of the page, in order to find the DC gain, it uses Final value theorem. Ok, well, let's assume somehow he put "0" where he saw "s". How...
  3. S

    Calculating ideal gas compressor work and final temperature

    A compressor is being used to adiabatically pressurize three moles of ideal gas from 5 bar and 150 C to 50 bar. Determine the minimum work that must be supplied to the compressor and the outlet temperature of the ideal gas. Assume the ideal gas has a constant pressure heat capacity of 29...
  4. collinsmark

    News USA Final 2012 Presidential Debate (#3) Observations

    'Guess I'll start the thread for this one too. Use this thread for commentary on the 3rd (final) Presidential Debate. It starts at 9PM EDT Oct 22nd. Please keep debate of issues to a minimum and focus on observations relevant to the debate itself. Have a nice day :) I'll be watching it...
  5. S

    Special relativity: What is the final mass of the rocket?

    Homework Statement Ok, the problem says some rocket of mass M0 has this new technology that allows it to convert photons into fuel. It reaches a speed of .5c. The problem asks us to solve for the final mass of the rocket, and then assume that all the lost mass was converted into photon fuel...
  6. S

    Change of Entropy Calculation - How to do this without Final Pressure Volume?

    Homework Statement I am having trouble working out the change in Entropy. The question is as follows: A mass of 1 kg of air is initially at 4.8 bar and 150 degC and it is enclosed in a rigid container. The air is heated until the temperature is 200 degC. Calculate the change in entropy...
  7. V

    Problem with calculating final temperature of water

    A piece of ice with a mass of 60 g is transferred directly from the freezer at a temperature of –7°C to a polystyrene cup containing 200 g of water at 75°C. Calculate the final temperature of the water. Ignore any heat loss to the cup and its surroundings. Qheat ice + Qmelt ice + Qheat cold...
  8. A

    Tricky problem worth 2 points on my final grade

    Tricky problem worth 2 points on my final grade :) Homework Statement Homework Equations I honestly don't know how to tackle this. I think it's going to contain ƩF=mg, and some basic kinematic equations. The Attempt at a Solution Where do is start?
  9. C

    Problem with Escape Velocity given final speed

    Homework Statement The radius of Mercury (from the center to just above the atmosphere) is 2440 km (2440103 m), and its mass is 0.31024 kg. An object is launched straight up from just above the atmosphere of Mercury. (a) What initial speed is needed so that when the object is far from Mercury...
  10. S

    2d Kinematics Problem Final Velocity

    Homework Statement http://imgur.com/fGYf0 Stuck on #3 Homework Equations V = Vi + a*t Y = (1/2)gt^2 + (ViY * t) + Yi The Attempt at a Solution I have found the vertical and horizontal components and the initial velocity. ViX = 6.2 ViY = 9.922 Vi = 11.7 Yf = 0 Yi = 7 Xi =...
  11. J

    Calling in all Electrical Engineers- Final Year Project help needed

    Calling in all Electrical Engineers- Final Year Project help needed! I needed some help from you guys regarding my Final year project. Basically my project is about a hydrogen fuel cell that charges the batteries in cars, its a hybrid system. The fuel cell is PEMFC (proton exchange membrane...
  12. D

    Archived Thermo I Question: Two vessels coming to equilibrium. Finding final values.

    Hey, guys. I am currently in a Thermo I class and have ran into a problem that has me completely stumped. I have worked in numerous different ways and anything I come up with doesn't seem to make since or be realistic. Here's the question: Two rigid vessels are connected by a small valve and...
  13. M

    Find the Initial and Final states of an excited Hydrogen Atom

    Homework Statement A hydrogen atom in an excited state absorbs a photon of wavelength 434 nm. What were the initial and final states of the hydrogen atom? Homework Equations 1/λ=1/91.127 * (1/nf2-1/ni2) The Attempt at a Solution Tried to use the equation, but keeping the initial...
  14. T

    Final Velocity given only Initial Velocity and Angle

    Homework Statement This is a homework that has me completely stumped. If anyone help me out here, I would greatly appreicate it. A billard ball is east at 2.0 m/s. A second, idential ball is shot west at 1.0 m/s. The balls have a glancing collision (not head-on), deflecting the second ball...
  15. M

    Specific heat capacity and final temperature

    Homework Statement A 2.8 kg sample of a metal with a specific heat of 0.43KJ/KgC is heated to 100.0C then placed in a 50.0 g sample of water at 30.0C.* What is the final temperature of the metal and the water? Homework Equations heat loss by the metal = heat gain by the water The...
  16. D

    Half-life decomposition, find final concentration

    Homework Statement In a first order decomposition in which the rate constant is 0.03 sec-1, how much of the compound (in mol/L) is left after 39 sec, if there was 2.00 mol/L at the start? I'm using a few equations and trying to plug it in but I don't know whether they are appropriate or not...
  17. X

    Two ways to calculate the final speed of a rotating cylinder

    Situation: A uniform cylinder (Mass M, Radius R) is rotating down a slope of incline θ and distance s, there are two methods which I used to calculate the final speed, one of which considered forces acting on the cylinder and the other using energy, pure rolling assumed throughout, both give...
  18. D

    How do i find the final velocity with 2 height variables and gravity

    1.A tennis ball is dropped from 1.3 m above the ground. It rebounds to a height of 0.956 m. With what velocity does it hit the ground? The acceleration of gravity is 9.8 m/s^2 (Let down be negative.) Answer in units of m/s 2.With what velocity does it leave the ground? Answer in units of m/s...
  19. T

    Final temperature in reversible expansion

    Homework Statement One mole of an ideal monatomic gas initially at volume Vi and temperature 1000k expands to a final volume Cvi in three reversible steps: 1) isothermal expansion from Vi to aVi, 2) adiabatic expansion from aVi to bVi and 3) isothermal expansion from bVi to Cvi In terms...
  20. A

    Medical Suggestions for my final year project

    I am biomedical enginerring student, I am working to gather Ideas for my graduation project and I will appreciate if anyone provides me with some ideas and some relaible sources (if any) for any innovative biomedical engineering project
  21. M

    Virtual Image Location for Negative Lens System?

    Homework Statement S is a lighted object, height=1. what is the final image that is created by the system? Homework Equations The Attempt at a Solution i just don't understand how do i find the location of a virtual image created by a negative lens when the rays converge to a...
  22. J

    How to get initial and final velocity? thanks

    Homework Statement a human cannonball in 1940 soared over three ferris wheels, each 18 meters high covering a horizontal distance of 10.63 meters. Assuming that the point of projection is 2.50 meters above the ground and that he landed safely on a net placed at the same level, find his initial...
  23. C

    Help Me Study for the Final: Answers Needed!

    These exams are merely help for studying for the final in this class. Completing them will not give me any credit whatsoever or affect my grade in the course. The only problem is that our instructor did not give us answers to the tests so we have no idea whether or not we worked the problem...
  24. K

    Final concentrations unknown volume

    Hi I have a known volume of water with a known concentration of calcium. I want to bring that volume up to a new (slightly) higher volume with a new (slightly) higher concentration. To do this I am adding a solution with a known concentration of Ca but cannot remember how to calculate the...
  25. A

    Final State Tank Homework: Solving E_out,mass Integral

    Homework Statement Given a tank filled with gas, you are to pump out a given amount and find the final state of the tank. Given the volume, gas (non-ideal), amount of gas in tank, flow rate, temperature and pressure, all at state 1. We can find density at state 2 from the tables, but we need...
  26. N

    Determining final temperature, pressure and work done

    hi guys I am swamp with work and have not been able to go through my assignments proper [b]1. one cube meter of an ideal gas at 600K and 1000Kpa expands to 5 times its initial volume: by mechanically reversible, isothermal process and by a mechanically reversible, adiabatic process...
  27. dlgoff

    Yes. Murray in final at Wimbledon

    Finally. Federer to face Murray in Wimbledon final http://www.usatoday.com/sports/tennis/story/2012-07-06/wimbledon-mens-semifinals-roger-federer-novak-djokovic-andy-murray/56059932/1
  28. T

    Final charges on the capacitors

    Homework Statement [SIZE="3"]The Problem is as follows :- https://fbcdn-sphotos-a.akamaihd.net/hphotos-ak-snc6/224892_2277870043526_218311126_n.jpg Three capacitors of 2 μF, 3μF, and 5μF are indulgently charged with batteries of emf’s 5V,20V and 10V respectively. After...
  29. Z

    Physics Final Exam Sample Question

    Homework Statement A hockey puck of mass 0.200kg is sliding along a smooth, flat section of ice at 18.0m/s when it encounters a patch of snow. After 2.50s of sliding through the snow it returns to smooth ice, continuing at speed of 10.0m/s. a) What is the change in momentum of the puck...
  30. S

    Electric Fields , Finding final velocity. NEED HELP

    Homework Statement Mass= 15g Q1= 8.0uC Q2= 25 uC (stationary) Q1 is released from a point 12cm from Q2. How fast will Q1 be moving when the separation is 20cm. Homework Equations F=ma F=qe F=kQq/r2 E=kQ/r2 Ke=mv2/2 W=FD vf2=vi2+2ad The Attempt at a Solution...
  31. S

    Preparing for Physics Final: Understanding Waves and Frequencies

    What's going on, guys. I have a Physics final tomorrow, and I don't understand these! "What is the frequency of a wave that has a speed of 3 m/s and a wavelength of 8 m?'' "What is the period of a wave that has a frequency of 5 Hz?" I'm assuming they're all simple, so if someone can...
  32. P

    Thermo-Chem, Final Temp of a Mixture

    Homework Statement A 155-g piece of copper at 188oC is dropped into 250.0 g of water at 23.7oC. (The specific heat of copper is 0.385 J/goC.) Calculate the final temperature of the mixture. (Assume no heat loss to the surroundings.) Knowns. 155g Copper Initial Temp 188 C 250.0g Water Initial...
  33. R

    Final temperature of diamond using Cv

    Homework Statement At low temperatures, Cv of solids is given by: [SIZE="4"]Cv = D(\frac{T}{\Theta})3 where: D = 1.94*10^3 \Theta = Debye Temperature, for diamond 1860K If 100J of heat is transferred to 1mole of diamond, initially at 10K. Calculate the final temperature...
  34. G

    Final Temperature of Combustion Gases

    Hopefully one of you guys can help me out.. I'm designing a burner that will run off powdered biofuel and I'm trying to calculate the resulting temperature after combustion. I have a higher heating value (HHV) of around 10,000 BTU/lb for the biofuel and for a complete stoichiometric...
  35. M

    Calculating Final Speed in Elastic collision (momentum)

    Homework Statement If it is eg. two balls, both going to the right before and after an elastic shock, how do you determine their velocities after the collision? (speeds before and weights are given) Eg. M = 50 kg u1 = 20 m / sm = 100 kg v1 = 10 m / s (M, m = mass) (u1, v1 = velocity before...
  36. M

    Finding final temperature of a mixture

    Homework Statement calculate the final temperature when 20 grams of steam at 100°C is added to 100 grams of ice at -40°C. Homework Equations Q=mcΔt and Q=ML The Attempt at a Solution I tried solving this problem using -ΔQheat = ΔQcold, but the final temperature that I found was past...
  37. Drakkith

    What comes next after 9 years of active duty in the Air Force?

    This is it. 9 years, 11 months, 16 days of active duty Air Force and today is my final day. It's been good and bad. I'm looking at going reserve and moving to Tuscon to go to the University of Arizona to do Optical Engineering if everything goes well. Off to my final out appointment! SSgt...
  38. N

    Gas law, how to fine the final T and Final P?

    i don’t understand how they got this answer can you please explain the steps needed to fine the Final T and How the final P was found. thanks N2H4 + 3O2 ==> 2NO2 + 2H2O assume there are 60 moles of O2, what is the final T and P V = 20L T1 = 290K n (N2H4) = 20 Cp = 57 kJ/C...
  39. G

    Solving the 2D laplace equation. Quick question about the final stage

    Homework Statement ## \frac{\partial^2 V}{\partial x^2} +\frac{\partial^2 V}{\partial y^2} = 0 ## it's defined for ##V=0 ## for ## x=0, 0<y<b##, ## x=a, 0<y<b##, ## y=0, 0<x<a## ##V=V_0 x/a ## for ## y=b, 0<x<a## Homework Equations None. The Attempt at a Solution I've got ##V(x,b) =...
  40. 0

    Physics final prep, question about force under water at depth h

    Homework Statement The question states: The fresh water behind a reservoir dam has depth D=15 meters. A horizontal pipe 4.0cm in diameter passes through the dam at depth d=6.0m. A plug secures the pipe opening. (a) Find the magnitude of the frictional force between plug and pipe wall...
  41. M

    Preparing for a phys final, springs and bouyancy

    Hey all, I am a little confused on this, I was trying to study and these two questions came up... I guess i am confused, I don't know the solutions and I want to know which it is and why... 1. A helium balloon is observed to rise up into the air at the front of the classroom, and is only...
  42. M

    How Does a Police Car Catch Up to a Speeding Vehicle?

    1. While driving on the highway at a constant speed v0, significantly above the speed limit, you pass in front of a parked police car without noticing it. After a few seconds, during which time you have moved a distance d, the police car starts chasing you with a constant acceleration a0. Give...
  43. M

    Acura/Bentley: FINAL EXAM REVIEW

    1. Two cars, an Acura and a Bentley, are initially at rest a distance L from each other. At time t = 0 both cars starts accelerating toward each other, with constant acceleration Aa amd Ab respectively, until they crash into each other. a) At what time does the crash happen? b) Find the...
  44. R

    Testing Should I Give Up and Turn in My Final Exam Now or Keep Working on It?

    I'm working on a unlimited time final exam. There is a problem that I have been thinking about for the last three days but I still couldn't get it. It is worth about 15% of the final and the final is 35% of my grade. I could work on the final for another 5 days before I turn it in. Now the...
  45. M

    Final Exam Review: Motion of an Airplane

    This is a question from an old test that I took this semester. My grader did not input anything, so I am left to trying to figure out by myself if my answers are correct or not. Question: The motion of an airplane leaving from miami can be described using a cartesian coordinate system with...
  46. R

    What Is the Final Temperature of a Mixed Gas in a Thermally Insulated Enclosure?

    Homework Statement I need some help with the following problem: Consider a thermally insulated enclosure containing an ideal gas initially separated by a thermally insulated partition into two separate regions. One region is at pressure p1=100 Pa, temprature T1=200 K, and volume V1 = 10 m3...
  47. R

    Thermal contact final temprature

    Homework Statement The following is a worked problem from my textbook: Consider two masses, with initial tempratures T1 and T2 are placed in contact and isolated from their surroundings. They are CV1T1 + CV2T2 = CV1Tf+CV2Tf This equation can be solved for the final temprature T_f =...
  48. B

    Testing Navigating a Classical Mechanics Final with 11 Hours to Prepare

    Ok, so I feel really bummed out even having to ask this question, but in all seriousness: I have a classical mechanics final in 11 hours. It's upper division CM not like first year stuff. Anyway, I'm decently prepared. I mean, if I take it now I will certainly pass. But I want the best...
  49. I

    Final exam - help- Inverse function Theorem

    Homework Statement Let f(x) = sinh(x) and let g be the inverse function of f. Using inverse function theorem, obtain g'(y) explicitly, a formula in y. Okay the Inverse function Theorem says (f^-1)'(y) = 1/(f'(x)) If f is continuous on [a, b} and differentiable with f'(x)\neq0 for all x\in[a...
  50. K

    Latent heat and final temperature

    Homework Statement An aluminum container whose mass is 205g contains 300g of water at 20°C. In this container is then placed 250g of iron at 150°C and 20g of ice at -10°C. Find the final temperature of the mixture. Given: mAl=205g mH2O=300g TAl1=TH2O1=20°C mFe=250g mice=20g TFe=150°C...
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