Why don't hair particles rendered as an object follow parent object when the parent object is falling under gravity as a rigid body? I  have an issue where i have a cube mesh, I create hair particles, and set the hair to render as an object, say a cylinder.  I then enable rigid body physics for the cube. I also have a passive plane below the cube.  When I run an animation, the cube falls as if under gravity and stops at the plane, but the cylinder particles remain in their original position?

If I add soft body physics to the cube and order the soft body physics before the particle settings, then the cylinders fall, but lag behind the cube.  The cube falls through the plane below, but the cylinders are stopped by the plane?



Here with soft body added (to top of stack).  Particles do fall but have a lower acceleration rate, and the cube no longer detects the floor and passes through the plane?!
I probably need some screenshots, but I'll give it a shot:
Blender hair physics cannot get the same physical behaviour as their visualized object. Not that the object gets inserted in the "Render" tab, not the physics tab. Hair have their own strand based physics, which are limited. Unfortunately (to my knowledge and frustration) you cannot even make the rendered object bend along the hair's path. 
If that wasn't your question, make sure you did this: 


If your using softbody, make sure they are above the hair in the modifier stack. And lastly, make sure to bake the rigidbody animation to keyframes. 

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