momentum vs gravity

[Jonix]

Hello!

In my project for the iPhone I need to have falling objects that may be guided by changing the direction of the gravity force (accelerometer driven). However, the objects gain momentum very fast (not sure that momentum is the right word, I'm not a native-speaker, sorry). By that, I mean that though gravity can be changed it has little to no effect when objects reach certain velocity level.
I need to have these objects more affected by the gravity changes even at high velocities. Can this be done with Chipmunk?