1. Static friction cannot do work (correct?). Yet that is the only external force acting on an accelerating bicycle. How can these two ideas jibe? My thought is that the human is like a battery with potential energy, which, while being depleted, is *redirected* in some sense by the static friction. But I do not know if that is correct, or how it could be rigorously expressed.
2. (And this is *totally* unrelated to 1, other than that it has to do with bicycles). Is there a way to consider gear ratios/mechanical advantage, only in terms of torque/forces and not with energy? (I think there must be.) The only way I know how to think about the gear ratios is to say that if X force operates over A distance, and that causes Y force over B distance, AX = BY (if no energy leaves the system), by conservation of energy.
Thanks for the help! These problems have really be frustrating me during my bike rides recently...
2. (And this is *totally* unrelated to 1, other than that it has to do with bicycles). Is there a way to consider gear ratios/mechanical advantage, only in terms of torque/forces and not with energy? (I think there must be.) The only way I know how to think about the gear ratios is to say that if X force operates over A distance, and that causes Y force over B distance, AX = BY (if no energy leaves the system), by conservation of energy.
Thanks for the help! These problems have really be frustrating me during my bike rides recently...