Re: [Phys-L] [**External**] Lenz's law
If I drop a box onto a moving conveyor belt - the sliding friction will do
POSITIVE work until the speeds match.
Yes, it’s relative to which reference frame is chosen.
> On Apr 25, 2024, at 2:20 PM, stefan jeglinski <jeglin@4pi.com> wrote:
>
> Would we say this is similar to friction? We say the work done by sliding
> friction is negative, and we justify this by saying either that delta K is
> negative (object slows down) or the force is pointed opposite to the
> displacement, but it still depends on our *belief* that the friction force is
> pointed opposite to the displacement. In the annals of observation, this one
> appears to be ironclad but it does sometimes seem lacking to just say "well
> if it weren't true then energy wouldn't be conserved." If that's the best we
> can do then I'm good with it, but I do prefer to level with a student that
> maybe "that's the best we can do."
>
> Stefan Jeglinski