hardness and collision

[youssouf@univ-lyon1.fr (D Ismaël Youssouf)]

> > Dear phys-l member,=20
> >
> >  I have been very pleased to follow the discussion about the conservation=
 of energy. I would like to initiate another discussion (it would be very=
 useful for my work).

         I am a PhD student at Lyon University (France) and my current work =
deals
> > with a historical study of the "hard body", the "elastic body" and the
> > "soft body" concepts, mainly throughout two contests devoted to the proble=
m
> > (1668, the London Royal Society contest with Huygens, Wren and Wallis as
> > contenders, 1724 the Paris Acad=E9mie des Sciences contest with the
> > participation of Mac Laurin and Bernoulli).
> >
> >        I will also undertake a sketch of nowadays physicists ideas about =
 the kinematic behavior of "hard", "elastic" and "soft" bodies during=
 free-fall or collision experiments.
> > For example, I would like to know
> >
> >                        - accurate definitions of hard, elastic and soft
> > bodies.
> >                        - if for physicist hard bodies are able to rebound
> > after a free fall.
> >                        -the link between matter's
> > properties (elasticity, hardness, sofness) and the conservation of the
> > energy.
> >
> >
> >
> >
> >        So, I would be very grateful if you could be of some help for me.
> >
> >
> >
> >       Many thanks (and apologizes for my poor English).
> >
> >        Yours sincerely.
> >
> >                                D. Isma=EBl Youssouf.