How to make one clip increase its hight while the other movie clip as its but moving

programming flash
1

Hi,

I have a movieClip called RopeWithHook_mc. Inside this moviclip, I have 2 more clips called:
Rope_mc
Hook_mc
What I need is, when click on “Start_btn”, the rope hight should increase downwards but the Hook_mc size should not change and always hung to rope’s end as the rope moves downwards.

How can I do this.

Thanks in advance for any assistance.