Concept explainers
a)
The mass of the iron block.
a)
Answer to Problem 158P
The mass of the iron block is
Explanation of Solution
Write the expression for the energy balance equation for closed system.
Here, energy transfer into the control volume is
Write the expression to calculate the mass of the water.
Here, density of the water is
Write the expression to calculate the total work done by the paddle wheel.
Here, rate of paddle wheel by fan is
Conclusion:
Substitute
Here, change in total internal energy for iron is
From the Table A-3E, “the properties of common liquids, solids and foods table”, select the density of water at room temperature as
Substitute
Substitute
From the Table A-3E, “the properties of common liquids, solids and foods table”, select the specific heat at constant pressure at room temperature for water and iron as
Substitute
Thus, the mass of the iron block is
b)
The entropy generation during the process.
b)
Answer to Problem 158P
The entropy generation during the process is
Explanation of Solution
Write the expression for the entropy balance equation of the system.
Here, rate of net entropy in is
Conclusion:
Substitute 0 for
Substitute
Thus, the entropy generation during the process is
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Chapter 7 Solutions
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