Re: [Phys-l] Collision of irregular bodies

["Bob LaMontagne" <rlamont@postoffice.providence.edu>]

I started to think of an extension to Brian's conical surface. I envisioned
two large balls each with an outrigger attached. At the end of the outrigger
there is a hemispherical piece of frictionless material. On one object the
hemisphere is convex and on the other it is concave. Let the collision occur
in such a way that the two hemispheres collide as the first contact between
the objects and in such a way that the convex one perfectly snuggles into
the concave one and that all the involved surface points contact
simultaneously. 

In the usual "plane of contact" collision, the force is perpendicular to the
plane. But in this case it appears that the force is parallel to the mutual
relative velocity vectors between the objects.

Bob at PC

> From: phys-l-bounces@carnot.physics.buffalo.edu [mailto:phys-l-
> bounces@carnot.physics.buffalo.edu] On Behalf Of R. McDermott
> Sent: Saturday, August 12, 2006 8:42 AM
> To: Forum for Physics Educators
> Subject: Re: [Phys-l] Collision of irregular bodies
>
> > If this third case comprised an object with an extrusive conical
> surface,
> >  and another object with an intrusive matching, coaxial conical surface,
> >  though exceptionally unlikely in the physics model universe, this union
> > would initially act like a high friction contact, no matter if the
> > surfaces
> >  were friction -free except if one rotated wrt the other on that axis.
>
> Agreed.  Now how about for a single point of contact?  Can the mass
> distribution, etc affect the direction of force as John D. implied?
>
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