When we push the wall, no work is being done. But we feel tired after some time. Since energy cannot be destroyed , the question is where does all the energy get transferred in this scenario.
Note : It cannot be all heat as we feel more tired than standing still and if it is being transferred in heat then why it is faster than standing still if no work is being done?
When we push the wall, no work is being done. But we feel tired after some time. Since energy cannot be destroyed , the question is where does all the energy get transferred in this scenario.
You need to distinguish between physical effort and physics work.
When you push on a wall and it doesn't move, your physical effort does not produce physics work. That is, you do not transfer energy to the wall. The energy expended is internal. Richard Feynman in his physics lectures explains it this way in connection with holding but not lifting a heavy weight:
The fact that we have to generate effort to hold up a weight is simply due to to the design of striated muscle. What happens is when a nerve impulse reaches a muscle fiber, the fiber gives a little twitch and then relaxes, so that when we hold something up , enormous volleys of nerve impulses are coming in to the muscle, large numbers of twitches are maintaining the weight, while other fibers relax. When we hold a heavy weight we get tired, begin to shake, ...because the muscle is tired and not reacting fast enough.
Note : It cannot be all heat as we feel more tired than standing still and if it is being transferred in heat then why it is faster than standing still if no work is being done?
It has nothing to do with heat. Heat is energy transfer due to temperature difference.
As I already indicated, when you push on a wall you do no physics work. But you expend chemical potential energy of your body when your muscle fibers alternatively "twitch and relax" as described by Feynman which makes you feel tired though you are not accomplishing anything. Think of it as internal physiological work as opposed to external physics work.
If you were able to move the wall you would be doing positive work. But still some of your chemical potential energy will be converted into internal thermal energy simply because your body is not 100% efficient in converting chemical potential energy into physics work.
Hope this helps.
For the same reason it takes energy to hold something up against gravity. Your body is not a rigid static structure that can support weight without consuming energy. Without energy, your body would collapse and topple over like a wet noodle.
When we push the wall, no work is being done.
No work is being done on the wall. Work is being done elsewhere (inside your muscles).
At a micro level, your muscles are both contracting (doing work, requiring energy) and slipping. Because the muscle fibers are slipping, energy is needed to hold position. This energy is converted to heat.
When you put a book on a table, it usually doesn't slip. No work is required to hold the book up against gravity. When you put a helicopter in the air, it falls or slips back down. Work is required to hold it in position. The same happens if you exert a strong force against a wall. The contracted muscles want to relax and require energy to hold the contracted position.
What is meant by energy here?you are giving a force to the wall.the wall will give an equal and opposite force because of the electron electron repulsion between the hand and wall(MOLECULAR LEVEL).you are getting tired because of the effort you are making and for that your hands and muscles need energy that energy will be produced by your own body duevto the glucose breakdown in your body cells.and that will lead you to inhale and exhale abit more and if you hold for a long time giving much more force you will be sweating too.the energy for that is produced by your own body cell it willbe released by your body.only the force is given to wall and cz its not moving no work is done no change in kinetic enrgy or gravitational potential energy.so i think pusing a wall and energy transfer throgh that cannot be related.
