VR Physics And Collision Detection In Hardware?

Alea asks: "Currently, a big chunk of the graphics pipeline, transform and lighting (T&L), is beginning to show up in graphics hardware. It seems likely that some other capabilities, such as collision detection, will follow. This means the main processor can be used to compute more sophisticated physics models for games and VR systems. However, it seems to me that many physical model computations could also be performed in hardware, freeing the processor for more sophisticated AI and conceptual modeling. Does anyone know if there is any work being done on implementing collision detection and simple physical models (e.g. momentum, gravity, friction) in hardware?"