Explaining How a Fridge & Meteorite Work With the First Law of Thermodynamics

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SUMMARY

The discussion centers on the application of the first law of thermodynamics, represented by the equation ΔU = Q + W, to explain the functioning of a fridge, the behavior of a meteorite, and the operation of a standard fan. A fridge operates as a reversed heat engine cycle, transferring heat from a cold reservoir to a hot reservoir by inputting work into the system. The kinetic energy of a meteorite is described as doing work on the Earth's atmosphere upon impact. In the case of a fan, it performs work on air by creating pressure differentials, resulting in airflow.

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  • Understanding of the first law of thermodynamics (ΔU = Q + W)
  • Knowledge of heat engine cycles and refrigeration principles
  • Familiarity with kinetic energy concepts
  • Basic principles of fluid dynamics related to airflow
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  • Research the principles of reversed heat engine cycles in refrigeration systems
  • Study the effects of meteorite impacts on atmospheric physics
  • Explore the mechanics of pressure differentials in fluid dynamics
  • Learn about the thermodynamic properties of gases in relation to work and energy transfer
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Jason_Hyde
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Hi,
I was woundering if somebody could explain to me using the equation
ΔU = Q + W (The first law of thermodynamics)
  • how a fridge works?
  • what happens with a meteorite?
  • what happens with a standard fan?
Much appreciated
--
Regards
Jason_Hyde
 
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Jason_Hyde said:
Hi,
I was woundering if somebody could explain to me using the equation
ΔU = Q + W (The first law of thermodynamics)
To be clear: W here is the work done to the system. Q is the heat flow into the system minus the heat flow out of the system.
  • how a fridge works?
  • what happens with a meteorite?
  • what happens with a standard fan?
We aren't going to give you the answer but we can help you find the answer.

The first question is a matter of applying the first law of thermodynamics to a reversed heat engine cycle (which extracts work from heat flowing from a hot to a cold reservoir) to cause heat to flow from a cold to a hot reservoir by adding work to the system.

For the second, think of the kinetic energy of the meteorite doing work on the Earth's atmosphere.

For the third example, think of the fan as doing work on air (a gas) by creating a low pressure on one side and a high pressure on the other.

AM
 

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