Recent content by MattHorbacz

  1. M

    Calculating expected RPM for a turbine blade.

    For my senior design project, my group is tasked with creating a wind turbine. At the moment, I am trying to figure out what approximate RPM the blades will rotate at so we can select an appropriate gear ratio and generator. Our advisor instructed us to use conservation of momentum on the...
  2. M

    Thermodynamics, use of Cv and Cp

    That makes more sense. But I still don't understand how you know to care about internal energy and not enthalpy. Is it just that for any case with ideal gasses consider internal energy?
  3. M

    Thermodynamics, use of Cv and Cp

    Why can that be used even though volume isn't constant?
  4. M

    Thermodynamics, use of Cv and Cp

    My mistake, I meant solving for Work, not heat
  5. M

    Thermodynamics, use of Cv and Cp

    I am studying for a thermo exam, and one of the problems I am doing deals with adiabatic expansion of a piston in a cylinder. When solving for work, the solution guide uses m*Cv*(T2-T1). I don't understand why they know how to use Cv instead of Cp. The pressure changes, so obviously you wouldn't...
  6. M

    Find entropy change when two tanks equalize

    I'm not sure if this was correct, but I calculated two ΔS, tank1 initial vs total and also tank2 initial vs total. I used the equation I listed above, then apparently you multiply each value for entropy by the mass then add the values...I think what I did was the right method, but I most...
  7. M

    Find entropy change when two tanks equalize

    Homework Statement Two rigid, insulated tanks are connected with a pipe and valve. One tank has 0.5 kg air at 200 kPa, 300 K and the other has 0.75 kg air at 100 kPa, 400 K. The valve is opened, and the air comes to a single uniform state without any heat transfer. Find the final temperature...
  8. M

    Power produced from alpha decay

    I looked it up at it seems to be about 6560 years
  9. M

    Power produced from alpha decay

    Homework Statement Assume that a 14 kg sample of 240Pu is used to produce electrical power from its α decay. If your device is 60% efficient in producing electrical power, how much power can be produced? (in watts) Homework Equations Q=mass of plutonium-mass alpha-mass daughter; 240 plutonium=...
  10. M

    Finding vC(t) for a Critical Damping RLC Circuit

    Homework Statement In the circuit in the following figure, the resistor is adjusted for critical damping. The initial capacitor voltage is 15 V, and the initial inductor current is 6 mA and R=1250 ohms Find vC(t) for t≥0. Express your answer in terms of t, where t is in milliseconds...
  11. M

    Find the resistance for maximum power transfer

    OMG I GOT IT RIGHT! THE ANSWER WAS 5 OHMS...gneill was right, the problem was in the negative sign. Thanks! you guys are the best!
  12. M

    Find the resistance for maximum power transfer

    yes, but we are already given R_L...i need to solve for R to maximize the output power on R_L
  13. M

    Circular Orbit / Practice Quiz #4, Question 27

    yes exactly...M in this case is the mass of the earth...it appears that they want you to look it up yourself...it happens to be 5.972*10^24 kg ALSO! don't forget that your radius is actually radius of Earth + objects distance from earth
  14. M

    Find the resistance for maximum power transfer

    yeah i realized that wouldn't work, but a man can dream =]
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