Physics final Exam prep

  1. Inceased  use of  fossil fuels since the beginning of the industrial age hasincreased the carbondioxide concentration in the atmosphere by____ and  has increased the earths temp.
  2. in 2009 what % of energy consumption in the US was provided by renewables
  3. Global demand  for energy has ___ over the past 50 years and might ___ in the next 30
    tripled, doubled
  4. when ws the steam engine invented?
  5. The US consumes ____ times the  worlds avg. energy per  capita.
  6. Conservation technologies can be put to use more quickly than we can increase supplies. For example, it takes _____ years to contruct a nuclear power plan but conservation practice can begine immediatley because the technology is available and simple
    9 to11
  7. The chemical  energy stored within oil may be considered as ____ associated with  molecular bonds, which are changed or broken during combustion
    Potential Energy
  8. What is the type energy associated with an objects motion
  9. The SI unit for force is
  10. In the equation for work, it is important that  the force is applied?
    in the direction of the motion
  11. __ is the rate of doing work
  12. F=MA is a statement of which of newtons laws  of motion
    Second Law of Motion
  13. _____ is the tendency of all objects to resist changes in their motion
  14. T or F. In an isolated system the cahnge in the total energy will always be zero
  15. T or F. Energy conservation and conservation of energy are really a statement of the same thing?
  16. In fossil Fuel power plant which are energy inputs?
    Air into boiler, Cooling water to condenser, Fuel into boiler
  17. In a multistep process the overall efficiency is equal to the____ of  the individual efficiencies.
  18. What is the typical efficiency of a fossil fueled power plant
  19. When talking about energy quantities of various fuels it is best to speak in terms of >
    Heating Value
  20. Which is a larger amount of energy. 1 Btu or 1 calorie.
    1 btu
  21. buildings account for ____ of the elctricity use in US
  22. Heat  is_____
    The energy transferred between bodies due to a temp difference
  23. A heat engine...
    converts heat energy into mechanical energy
  24. The quantity of heat that must be added per unit mass at the solids melting point to convert it entirely to a liquid at the same temperature is call the _____ of the material
    heat of fusion
  25. As liquid changes into a vapor
    Heat energy is being absorbed
  26. A hot object with a high specific heat cools down more quickly than an objec with a low specific heat T or F
  27. Why does carpet feel warmer than tile?
    Tile has a higher thermal Conductivity therefore can conduct the heat from foot more effectively
  28. Draw a phase change diagram>>> Include Temp, Heat input, Tmelt, Tboil, Solid, Liquid, Gas
  29. Difference between heat and temp?
    Heat is the flow of energy from one body to another due to temp difference.

    Temp is the measure of the kinetic energy of molecules in material
  30. Explain why transformers only work with Ac.
    Include 2nd connection of magnet and electricity.
    • Based on 2nd connection between electric/magnet. A changing magnetic field excites the flow of electrons. 
    •    Therefore the only way 2 induce the flow of electrcity in the 2nd coil is for the iron core 2 have a changing field only accomplished by AC
  31. Why do we transmit electricity over our electric grid w/ac @ high voltages
    • Transmission is all about minimizing power loss in transit.
    •  Power is proportional 2 current. We must minimize current to minimize power loss. This can be done by switching voltage for current which is accomplished through a transformer and that only works by ac .
  32. Thermohaline circulation derived from two words.
    • Thermo=HEat
    • Haline=Salinity
  33. V=IR is statement  to whos law
  34. As more devices are added to a series circuit the current  or  resistance increases
  35. Heat transferred through fluids primarily by the motion of the gas or liquid is called
  36. Heat transfer by radiation requires a medium with a high specific heat value T or F
  37. All types of electromagnetic radiation have the same velocity in a vacuum
  38. Hotter objects emit EM radiation with a wavelength that is ____ than cooler objects
  39. A heat engine_____
    Needs a temperature difference to be able  to work
  40. A cycle in which the working fluid changes state is called a
    Rankine Cycle
  41. The maximum efficiency of a heat engine operating between 2 degrees C and 200 degrees C will be about___
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Physics final Exam prep