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posted by  yuuri on 8/7/2008 8:05:10 AM  |  status: Closed  

thermo problem set..

Course Textbook Chapter Problem
Thermodynamics Engineering Thermodynamics, 4th edition, M. David Burghardt N/A N/A
Question Details:

    An insulated 2-kg box falls from a balloon 3.5 km above the earth. What is the change in internal energy of the box after it has hit the earth’s surface?

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posted by bradely(SME Mechan on 8/7/2008 10:44:26 PM  |  status: Live
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yuuri's comment:
"thank you, its the correct answer..."
Response Details:
m=2kg
g=9.81m/s2
h=3.5 km
  =3500 m
Change in internal energy=Potential energy
Change in internal energy=mgh
                                      =(2)(9.81)(3500)
                                      =68670 J
                                      =68.67 kJ
 
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