Works with Unity 3.5.0 and upwards
Force Arrows is a physics package that makes applying forces to rigidbodies much easier.
You simply drag a ForceArrow prefab to your scene, point it in the direction you want the force to act, drag a script to the game objects you want to move, set a bunch of numbers, and watch what happens. No need to waste time...
Force Arrows - apply forces to rigidbodies [Released]