Timeline for How does friction increase energy of a system?
Current License: CC BY-SA 3.0
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| Nov 30, 2017 at 16:44 | comment | added | Rick | Yes, from Newton's laws -In order for the man to accelerate from rest, there must be an external force on him, which is (static) friction. But that friction does no work (as your foot doesn't slip), The energy comes from your muscles, not from the ground. That's why you feel tired and your legs ache after walking too much. Think about what actually happens when you walk, you put one foot forward, push the ground with it (the reaction force helps you move your COM ahead) , then lift your other leg with your muscles and move ahead.) Friction is necessary for walking, but it doesn't do work. | |
| Nov 30, 2017 at 16:19 | vote | accept | Atharva Kulkarni | ||
| Nov 30, 2017 at 16:19 | vote | accept | Atharva Kulkarni | ||
| Nov 30, 2017 at 16:19 | |||||
| Nov 30, 2017 at 16:00 | comment | added | Atharva Kulkarni | Please read the above comment :) | |
| Nov 30, 2017 at 15:52 | comment | added | Atharva Kulkarni | @safesphere As the man is moving forward from rest, can't we say that a net external force must be acting on him in that direction ?? If we take work done as change in KE, there is a positive work done on him. As muscles are a part of our body and any action by them would result in motion of only particular parts of our body, the velocity of CoM of man's body will remain zero. So how will the muscles do work on the body ?? | |
| Nov 30, 2017 at 15:04 | history | edited | Rick | CC BY-SA 3.0 |
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| Nov 30, 2017 at 14:57 | history | edited | Rick | CC BY-SA 3.0 |
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| Nov 30, 2017 at 14:45 | history | answered | Rick | CC BY-SA 3.0 |