Physics 29 Efficiency Of Heat Engines (4 of 14) Second Law of Thermodynamics (Entropy)

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I just found all your videos, and ilecture website. Absolutely brilliant! Simple, well explained. Shorter videos like yours are easier for busy people to watch as time permits. Great resource! Thanks for making these!

[@MichelvanBiezen]

I appreciate the feedback, thank you.

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I just want to say, You are one of the best Physics teachers alive!!! Thanks for your clear explanations really wish I found you videos at the beginning of my class year.

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Gonna binge watch these thermo vids since my year 2 thermo exam is next week, appreciate the work you put in them

[@MichelvanBiezen]

You'll find everything you need to know in these playlists. Good luck on your exam next week.

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thats man amazing, always come here before exams. your english is simple so i can understand. thank you for this.

[@smailwaltit38]

Thank you professor Michel for all the uploaded videos

[@Obletix]

The last example ( Ice to Water ) seems to contradict the first statement of entropy "A measure of the amount of energy that is unavailable for work". There seems to be another law dictating the order you observe in water when removing heat.

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Thank you professor for all the videos... tremendous work.... great explanation

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i learnt from these videos more than what i learnt from the university where I'm paying $10,000 a semester. I feel I am being ripped off.

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i had a great rank due to this i will always be in debt to you

[@MichelvanBiezen]

The credit goes to you for all your hard work. We are just glad we were able to help.

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Your videos are amazing!

[@JRockTT]

Thank you so much! Your explanation was wonderful!!

[@MichelvanBiezen]

You're very welcome!

[@wasgehtab1]

you make the best videos. Thank you so much!

[@dsaints101749]

I'm not so sure if I perfectly understood your explanation about entropy. If entropy is a measure of the amount of energy that is unavailable for work as in the exhaust gas of heat engines, then how come that some cars are designed to recover the available heat energy from the said exhaust gas to drive or work on the turbo charger in order to increase the power output of an engine.

[@rationalthinker9612]

He actually addressed that in a previous video. The output of heat aka Qc would have to be zero and all the input heat aka Qh would have to be converted to work leaving no heat for output. That implies that Qc would be absolute zero which is not possible

[@NOBOX7]

would it be safe to say Entropy is analogous to Overhead in a Business and Work is the available profit in that business plan ? i know this is far from the entire story im just looking at the picture far left and Entropy is like the cost of the work provided in a sense based on that plan a better design would alter the specifications or "Profit margin" im referring specifically to heat engines only

[@historyisthebest5831]

I'm sorry sir there seems to be a confusion (not in your video). Many of my practice problems include efficiencies of the body metabolizing food energy and how it does work and cause heat to transfer out. Does doing work(work done on outside) cause heat to transfer out of a system?(sorry looks like I'm walking way back to the starting point) And what's the efficiency of the body in converting food energy? A man does 35000J of work and his efficiency is 5%, what's the energy being metabolized and what's the heat transfer to the environment? What's the metabolism efficiency? Is it delta U / w or w / delta U?

[@fahimfaysal4794]

Sir,Energy is defined as the power to do work..and entropy is defined as energy that is unavailable for work..so if the energy is not available for work..how we could define it as energy?

[@MichelvanBiezen]

You have to make a distinction between mechanical energy and thermal energy. Thermal energy requires an engine to make it available to do work.

[@fahimfaysal4794]

Michel van Biezen Thank you sir!Then the entropy is a calculation of thermal energy that is unavailable for work?

[@MichelvanBiezen]

No, entropy is not energy. The units are J/K. But it is a measure of the distribution of energy as a function of the temperature it is stored at. It is also a measure of the separation of heat (again as a function of temperature). As entropy increases, the temperature variation of the universe will decrease.

[@ellyvatedaf]

0:33 made the eventual heat death of the universe click for me. One day, the universe won't have any more free energy to increase entropy!

[@zahrahussain7577]

now I get it ,thank you

[@as_salafi_gadgets]

Thank you sir

[@MichelvanBiezen]

Welcome. Glad it helped.

[@faicornelius2601]

entropy or Enthalpy

[@MichelvanBiezen]

In this video we are discussing entropy

[@zahrahussain7577]

when water became ice we are giving it energy but with out doing any thing it is normal to see ice became water

[@peterv6i]

thank you