[Phys-L] Re: A Third law question

[dwilley+ at PITT.EDU (David Willey)]

Rick Tarara wrote:

> .....'Where does the disk get the
> extra force when I push up with more force than its weight?' was her
> repeated question.
>
> Any suggestions here?
Think of pushing up on the string of a bow held horizontally. When you
push up the bow deforms, that's where the "extra" force came from. It's
just the disk didn't change its shape noticeably. Even balancing a 2m
stick on her hand would work, push up quickly on the middle and you'll
see the ruler change shape,
cheers,
David