Never thought I'd say it but here's a demo of a cool bit of software that Microsoft wrote as a PowerToy for the Tablet PC. It's called 'Physics Iluustrator'
It's a good job I haven't got it on mine as I'd never get the car built

[Edited on 5/5/07 by bodger]

cool, but it looks alot like working model 2d

Very cool.

Just had a download and play. Not half as straight forward as the video shows, but managed to have a "car" boucing down a slope although its wheels and body were separate.

Will have to rtfm.