How can I change the speed and direction of a dynamic object incrementally?
For example, if the air touches a circular dynamic object how can I change the speed and direction of a dynamic object incrementally?
It depends on the direction of the air
Do you have events or a screenshot of your scene? Where is the force coming from? A pipe, a machine, Mother Nature? The physics behavior has a lot of ways to apply force. You could calculate the force based on the distance between the object and some source. The closer the 2 objects, the stronger the force. The same for direction.
If distance < 500 then force = 500-distance
If distance < 500, force = 100-(distance/500) * 100
The functions lerp() and normalize() might be useful as well as the various functions for distance and angle.
What have you tried? What does the force and the target object represent?