Answer: 0.2m
Explanation: Firstly only the Rocket's Weight Compress the spring which can be found by
[tex]F_r=M_r*g\\F_r=10*9.81\\F_r=98.1N[/tex]
According to Hooks Law
[tex]F_r=k*x\\x=F_r/k\\x=98.1/480\\x=0.2m[/tex]
The part b and c of this question is done in the attachment