How to untie the hair to let the hair dynamic fall

Hi, i am noob for these part.

I have some problem as below:

  • the hair is “Jumping” around even the movement is stopped.

-it there any way to animate a untie hair from the start to end?

I do the hair dynamic on one piece with weight paint and collision object.

i do know the hair can be model separate then later joint to one, but if i do that i cant do the untie hair animation.

is there any solution on it?
it will be much appreciated for this.

Thanks.