Thermodynamis of air in a basketball

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SUMMARY

The discussion centers on the thermodynamics of air within a basketball during compression. The air, primarily nitrogen (N2), is initially at 20.0°C and 2.00 atm pressure, and upon compression to 80% of its original volume, the temperature rises to 47.4°C. The change in internal energy (ΔU) is calculated using the formula ΔU = nC_vΔT, where C_v is 20.76 J/(mol·K). The participant initially calculated ΔU as 0.00333657 J, but identified the need to apply the first law of thermodynamics, concluding that ΔU = -W, where W is the work done on the ball.

PREREQUISITES
  • Understanding of the ideal gas law and properties of gases
  • Familiarity with the first law of thermodynamics
  • Knowledge of specific heat capacities, particularly C_v
  • Basic algebra for manipulating thermodynamic equations
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  • Study the ideal gas law and its applications in thermodynamics
  • Learn about the first law of thermodynamics and its implications
  • Explore the concept of specific heat capacities, focusing on C_v for gases
  • Investigate the work done on gases during compression processes
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This discussion is beneficial for physics students, particularly those studying thermodynamics, as well as engineers and anyone interested in the physical principles governing gas behavior in confined spaces.

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Homework Statement


A player bounces a basketball on the floor, compressing it to 80.0 % of its original volume. The air (assume it is essentially N_2 gas) inside the ball is originally at a temperature of 20.0 C and a pressure of 2.00 atm. The ball's diameter is 23.9 cm

Temperature at maximum compression equals 47.4 C

By how much does the internal energy of the air change between the ball's original state and its maximum compression?
\DeltaU=?

Homework Equations



\DeltaU=nC_v\DeltaT
C_v=20.76

The Attempt at a Solution



n=.0000058657

\DeltaU=.00333657
but that's not right
 
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Start with the first law

Q-W=ΔU

now no heat is being added to the system so Q=0

You're left with ΔU= -W. What is the work done on the ball?
 


W=nC_v(T_1-T_2)
that is the same thing i was using
 

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