How imperfect is the human machine

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SUMMARY

The discussion centers on the energy expenditure of human muscles during physical activity, specifically when pulling or pushing a weight of 10 kg over a distance of 1 meter, which requires 10 joules of energy. Participants estimate that human muscle efficiency is around 20%, meaning that for every joule of work performed, approximately 4 to 5 joules are expended. This aligns with the principles of the second law of thermodynamics, which states that no system can achieve 100% efficiency. The conversation also references the need for energy to maintain muscle contraction, even when no work is done.

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  • Understanding of basic physics concepts such as energy, work, and efficiency
  • Familiarity with muscle physiology, particularly skeletal muscle contraction
  • Knowledge of thermodynamics, specifically the second law
  • Ability to interpret energy expenditure in joules and calories
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bobie
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If we pull/ push a weight of 10kg and dislocate it 1 meter the energy spent is 10 joules, can someone tell me roughly if 10 j is 100% can anyone tell me how much energy (calories) has been burned /wasted in excess? I suppose it can vary in different persons and by different factors, I'd like to get just a rough idea, 120%?
 
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For every Joule of work, you burn 4 to 5 Joules. Google muscle efficiency for more details.
 
Thanks, very helpful
 
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According to a book I'm reading, the human body is running roughly at 20% efficiency. Seeing that nothing can be at 100% efficiency (2nd law of thermodynamics) I'd say the human body is doing perfectly well.
 

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