Thank you!
There are in fact a whole host of free Plug-
Ins on the forum, for Physics you actually have a built in ODE Engine [Open Dynamics Engine] which is handy for basic physics interactions, and also useful for collisions which nobody really thinks to mention

you could also use what e
veryone says and that is Sparky\'s which you can look for and also have a fish around my Repository
http://www.akaneaya.com/tgcforumrepository/ in the DarkBit Archive...
There are quite a lot of free plug-ins around here I believe there is a thread for it too...
I am almost done with an update to PRIMER which will pave the way for me to work on PROTOTYPE, which will introduce the paid Plug-ins including the included ones...
[Included in DGS]
Did you not notice DGS? it includes Dark Physics which is very capable and easy to use... DGS is a good beginner pack to start with for DBPro...
I hope I can help further, if I can, just shout out