Hi,
I'd suggest posting what you've tried so people can see why it isn't working.
I haven't looked at Sparrow code in a while, though I still visit the forums every day, but one way to do this is with tweens. One of the first Sparrow tutorials covered a very similar example - Sparrow Balloon Game Tutorial - so i'd suggest taking a look.
The tutorial is based on Sparrow 1.0 but in 2.0 you only need change a few things for it to work:
1.0
self.stage
2.0
Sparrow.stage
1.0
removeTweensWithTarget
2.0
removeObjectsWithTarget
1.0
SP_EVENT_TYPE_TWEEN_COMPLETED
2.0
SP_EVENT_TYPE_REMOVE_FROM_JUGGLER