When I leave my room I walk down three flights of stairs releasing about 7kJ of potential energy. Where does it go? Is it all getting dispersed into heat and sound? Is that heat being generated at the point of impact between my feet and the ground, or is it within my muscles?
Related question, how much energy do I consume by walking? Obviously there's the work I'm doing against air resistance, but I feel like that doesn't account for all the energy I use when walking.
Best Answer
Make it simple. If a mass of your weight fell down the height of three flights of stairs through the air, when it landed where would the kinetic energy accumulated by falling go?
moving the earth for conservation of momentum
dissipated in heat on the ground
deformation of the matter of the weight
sound
That is why humans invented the stairs, to dissipate the kinetic energy acquired in small increments, in the same but in a non-human-frame-destructive way.