(a)
The work done on the lead block in the process.
(a)
Answer to Problem 77PQ
The work done on the lead block in the process is
Explanation of Solution
Given that the mass of the lead block is
Write the expression for the work done at constant pressure.
Here,
Write the expression for the change in the volume of lead block when its temperature changes.
Here,
Write the expression for the coefficient of volume expansion in terms of the coefficient of linear expansion.
Here,
Use expression (III) in (II).
Write the expression for the volume of the lead block in terms of its mass and density.
Here,
Use expression (V) in (IV).
Use expression (VI) in (I).
Conclusion:
Substitute
Therefore, the work done on the lead block when the temperature increases is
(b)
The amount of energy added to the block by heat in the process.
(b)
Answer to Problem 77PQ
The amount of energy added to the block by heat in the process is
Explanation of Solution
Write the expression for the heat added up into the block while heating.
Here,
Conclusion:
Substitute
Therefore, the amount of energy added to the block by heat is
(c)
The change in the internal energy of the block during the process.
(c)
Answer to Problem 77PQ
The change in thermal energy of the block during the process is
Explanation of Solution
The change in thermal energy of the block is equal to the sum of heat added up to the system and the work done.
Write the expression for the change in thermal energy of the block.
Here,
Conclusion:
Substitute
Therefore, the change in thermal energy of the block during the process is
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Chapter 21 Solutions
EBK PHYSICS FOR SCIENTISTS AND ENGINEER
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