I have some physics homework questions I need help with?

These are the only 4 questions I am having issues understanding. I have all my other homework questions finished but these ones especially the first one I just do not understand. 

1. A brass vat is 

11 m

 long at room temperature (20°C). How much longer is it when it contains boiling water at 1 atm pressure?

2. An aluminum wing on a passenger jet is 

27 m

 long when its temperature is 

17°C.

 At what temperature would the wing be 7 cm (0.07 m) shorter?

3. Air in a balloon does 

55 J

 of work while absorbing 

72 J

 of heat. What is its change in internal energy?

4. An apartment has the dimensions 16 m by 8 m by 5 m. The temperature is 25°C, and the relative humidity is 52 percent. What is the total mass (in kg) of water vapor in the air in the apartment?

1 Answer

Relevance
  • Anonymous
    4 weeks ago

    1. the change in length is

    length * thermal expansion coefficient * change in temp

    the change in temp is 80ºC

    look up the thermal coefficient for brass

    2. same idea; look up coefficient for aluminum

    3. 72J - 55J

    4. Look up the amount of water vapor for saturation at 25º. Take 52% of that and multiply by the volume of the room.

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