Is Newton's first law of motion applicable when walking?

[Einstein60]

Is Newton's first law of motion applicable when walking?

 

[Ibix]

It's always applicable. But walking is a complicated process of using forces to drive yourself along and support yourself, so a naive application of it (something like "walking at constant speed shouldn't tire me out at all") won't work.

 

[PeroK]

Is Newton's first law of motion applicable when walking?

If we assume that Newton's first law only applies to a body with no unbalnaced external forces, then the answer is no, it does not apply to a person walking.