There is no bug
as long as you respect the principle :
[quote]If you move objects by events (e.g. set X, set Y) or other behaviors (e.g. also adding 8 direction to a physics object), the physics simulation will do its best to keep up with what you've done. However, it is usually more realistic to achieve the same thing by applying forces and impulses to physics objects. This keeps everything "in the physics world" and realistic.[/quote]
Extract from the basic physics tutorial
Also I've set your yellow platform to be movable, else the force doesn't apply.
You have to tweak the values to find the behavior you want and think in terms of physics (forces/mass/constistency) and not just "I visually place my elements here and there".Kyatric2012-01-27 20:02:31