Guess I recommend doing that
        
             
        
        
        
Answer:
17.71N/m
Explanation:
The period of the spring is expressed according to the expression;

m is the mass of the object
k is the force constant
Given
m = 5.50kg
T = 3.50s
Substitute into the formula;

Hence the force constant of the spring is 17.71N/m
 
        
             
        
        
        
Answer:
The answer of the part (a) is v2 = 7.09 m/s
and the answer of the part (b) is vA1 = 5.25 m/s
Explanation:
Explanation of the both parts of answer  is in the following attachments
 
        
             
        
        
        
Answer:
8) d
9) c
<em>Hope this helps! :)</em>