Work Done When Walking: Yes or No?

[Miraj Kayastha]

If we start walking from rest, is work done while walking?
I think work is done because kinetic energy increases and if we come to rest the work done is again 0 at last.

Is this true?

 

[NascentOxygen]

Work is done on a number of levels when we walk. We leave footprints (that requires expenditure of energy) and particles of rubber get scuffed off (ditto). As we take each step we lift our weight on one side by a cm or two as we straighten our leg on that side from bent to fully straight. That's work, lifting your whole weight against gravity by a cm or two every pair of steps (and in the process we lift the weight of each lower leg by more than this).

If you were to walk half a mile, the energy you return to the Earth as you finally come to a standstill is a miniscule fraction of the energy you expended doing those myriad small repetitive work tasks involved in locomotion.

 

[Miraj Kayastha]

So do we gain kinetic energy?
And this may sound weird but when we walk we displace air. If so do we do work on air?

 

[nil1996]

Work is force times displacement.
So anything you displace you have to do work on it :)

 

[Miraj Kayastha]

then how do we calculate the work done on air?

 

[Chestermiller]

then how do we calculate the work done on air?

This is a do-able calculation, but it involves solution of complicated fluid mechanics equations, including viscous terms.

Chet