Re: [Phys-l] Interactive Physics Simulations

[Hugh Haskell <hhaskell@mindspring.com>]

At 09:04  -0400 10/9/06, Ron Curtin wrote:

> For those of you who use the IP simulation program:  Some of my students
> are trying to build a simulation of a rotation problem and having a
> problem.  The problem involves a vertical long rod, pivoted on the upper
> end.  The rod swings down and its lower end collides with wad of putty.
> It's supposed to stick to the small putty wad, and then the rod and
> putty swing up a bit and then temporarily stop.  We can't get the putty
> and the rod to stick together.  I've tried setting the elasticity of
> both at 0.  Does anyone out there know how to make the two objects
> collide and stick together? Thanks.

Making perfectly inelastic collisions has always been a problem for 
IP. If have talked to them about it and they always tell me that it 
is a difficult programming problem and they continue to work on it. I 
suggest adding a "trap" to the end of the rod, so the clay will get 
scooped into the trap and then won't be able to get back out. It's 
clumsy but it more or less works. There may be some conditional rules 
that you can use to change the characteristics of the rod at the 
moment of the collision, but I have never taken the time to learn how 
to do that one so I don't know if it is really possible.

If John Ertel is still around the list, he may have some suggestions.

Hugh
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Hugh Haskell
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<mailto:hhaskell@mindspring.com>

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