AP Physics B - Thermo

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AP Physics B - Thermo
2012-04-25 11:22:47

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  1. Kelvin conversion
  2. Heat transfer equation
  3. Heat necessary for phase change
    • L is the latent heat of the phase change
  4. Linear expansion
  5. Volume expansion
  6. Heat transfer rate
    • k is the thermal conductivity, A is cross-sct area, L is length, T is temp. difference between two sides
  7. Ideal gas law
  8. Boltzmann's constant
  9. average kinetic energy of ideal gas
  10. root-mean-square speed
    • M is molar mass (in kg), mu is molecular mass
  11. Liter
    0.001 cubic meters
  12. Ideal gas at STP
    22.4 L at 1 atm and 273 K
  13. Zeroth law of thermodynamics
    • Transitive property of thermal equilibrium
    • Heat flow = 0 in closed systems
  14. Work done by ideal gas (heat must be removed)
    • Positive when work is done on system, negative when system does work
  15. Work when pressure changes
    • Area under P-V curve
    • Increasing volume gives negative work, decreasing volume gives positive work
  16. First law of thermo
    • No phase changes.
    • For constant volume, W=0 and
  17. Isochoric process
    • No change in volume
    • Change in internal energy due entirely to heat transfer
  18. Isothermal process
    No temperature changes
  19. Adiabatic process
    Q = 0
  20. Efficiency of heat engines
    • Q_H is heat energy discarded
  21. Carnot cycle
    1. Isothermal expansion (absorbs heat from high-energy source and expands; because temp doesn't increase, all heat goes into work performed by expanding gas)

    2. Adiabatic expansion (system expands w/o exchanging heat w/ surroundings; it thus does negative work, so its internal energy and temperature decrease)

    3. Isothermal compression - environment does work on gas, and it discards heat to low-temperature reservoir rather than increasing internal energy

    4. Adiabatic compression - system compressed to initial state with no heat exchange, so its internal energy and temp increase
  22. Carnot efficiency