Drag and drop object
on touch set x,y start points
on release set x,y end points
To determine speed for object through something ike impulse applied:
with a simple approach, use the distance as a reference for power. ie The longer someone dragged, the bigger the impulse applied.
Or you could do something fancy, like, setting begin and end time of the drag too and comparing to distance traveled, then apply impulse proportianally.