Entropy change in an inelastic collision.

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SUMMARY

The discussion centers on calculating the change in entropy during an inelastic collision involving a 3 kg mass colliding with a stationary 9 kg mass. Participants highlight the formula for entropy change, ΔS = ΔQ/T, but note the challenge of determining heat (ΔQ) and temperature (T) for this scenario. The alternative approach using S = k ln (number of microstates) is suggested, emphasizing the need to calculate the number of microstates to find the difference in entropy. The conversation also addresses the transformation of lost kinetic energy into other forms, as total energy is conserved despite the inelastic nature of the collision.

PREREQUISITES
  • Understanding of thermodynamics principles, specifically entropy.
  • Familiarity with inelastic collisions and conservation of energy.
  • Knowledge of statistical mechanics, particularly the concept of microstates.
  • Basic proficiency in using the Boltzmann constant (k) in entropy calculations.
NEXT STEPS
  • Research the calculation of microstates in inelastic collisions.
  • Study the relationship between kinetic energy and other forms of energy in inelastic processes.
  • Explore advanced entropy calculations using statistical mechanics.
  • Learn about the implications of entropy change in thermodynamic systems.
USEFUL FOR

Students and professionals in physics, particularly those studying thermodynamics and mechanics, as well as researchers interested in entropy and energy transformations in collisions.

bbhill
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1. A 3 kg mass hits a stationary mass of 9 kg and sticks. What is the change in entropy?



So, I figure that I will need to [tex]\Delta[/tex]S = [tex]\Delta[/tex]Q[tex]/[/tex]T.

However, I don't know the heat or the temperature of this reaction, so this couldn't possibly be the way to evaluate.

So, I think I could use S = k ln (number of microstates) and find the difference between the initial and final values of S. However, how would I calculate the number of microstates for this system?
 
Physics news on Phys.org
Inelastic collisions do not conserve kinetic energy. Here, the kinetic energy after the collision is less than before. However, total energy is always conserved. So, to what kind of energy is the lost kinetic energy transformed?
 

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