Answer:
Reflective
Explanation:
The radiation pressure of the wave that totally absorbed is given by;

 and While the radiation pressure of the wave totally reflected is given by;

Now compare the two-equation you can clearly see that the pressure due to reflection is larger than absorption therefore the sail should be reflective. 
 
        
             
        
        
        
The net force is 12 N to the left.
        
                    
             
        
        
        
Answer:
     wo = 18.75 rev / s
Explanation:
This is an exercise in endowment kinematics, it indicates that the final angular velocity is w_f = 109 rad / s, the time to reach this velocity is t = 1.87 s and the deceleration a = 4.7 rad / s²
          w_f = w₀ - a t
          w₀ = w_f + a t
          w₀ = 109 + 4.7 1.87
          w₀ = 117.8 rad / s
let's reduce to revolutions / s
          w₀ = 117.8 rad / s (1 rev / 2pi rad)
          w₀ = 18.75 rev / s