Answer:
Definition of envelop
transitive verb
1: to enclose or enfold completely with or as if with a covering
2: to mount an attack on (an enemy's flank)
See the attached picture for answers
Answer: 0.2m
Explanation: Firstly only the Rocket's Weight Compress the spring which can be found by

According to Hooks Law

The part b and c of this question is done in the attachment
I believe there should be some sort of table attached. Unfortunately I cannot answer this question. Sorry!