|
|
 Originally Posted by Poopadoop
Doesn't each foot have to be moving in the opposite direction for that to work? I dunno about anyone else, but last I checked that's not what happens when you walk.
Walking is when you swing your legs in an opposing pendular fashion and oscillate your hips so that you transfer weight to the "backward" moving leg on each legs swing cycle, so that your CG moves forward.
Your legs are always moving in opposite directions relative to each other, or stationary w.r.t each other when you're walking.
I mean. Your point still works because when your right leg is moving forward you have angular momentum one way, but when your left leg is moving forward, you have angular momentum the other way, so on average, the net angular momentum is 0 kgm^2/s... unless you always twirl in circles when you walk, which would be entertaining, but socially awkward, I imagine.
***
In inertial reference frames, so long as 2 objects are changing their position relative to each other, then there is (are) some reference frame(s) in which those objects are moving in opposite directions (at least along the line which connects their CG's).
If we allow for relativistic and accelerating reference frames, then whether or not any 2 objects are moving w.r.t. each other is a matter of perspective. So the matter that objects which are not moving w.r.t. each other are never moving in opposite directions doesn't even hold.
|
Reply With Quote