Solution:
54 / 9 = 6 boxes.
        
             
        
        
        
(a) The distance of the image formed by the concave mirror is 19.1 cm.
(b) The image formed is diminished and real.
<h3>
Image distance </h3>
The distance of the image formed by the concave mirror is calculated as follows;
1/f = 1/v + 1/u
1/v = 1/f - 1/u
1/v = 1/15 - 1/70
1/v = 0.05238
v = 1/0.05238
v = 19.1 cm
The image distance is smaller than object distance, thus the image formed is diminished and real.
Learn more about concave mirror here: brainly.com/question/13164847
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Answer:
The velocity of mass 2m is  
Explanation:
From the question w are told that
      The mass of the billiard ball A is =m
      The initial speed  of the billiard ball A = 
 =1 m/s
     The mass of the billiard ball B is = 2 m
     The initial speed  of the billiard ball  B = 0
Let the final speed  of the billiard ball A  = 
Let The finial speed  of the billiard ball  B = 
       According to the law of conservation of Energy
                  
               Substituting values  
                 
Multiplying through by 
                 
     According to the law of conservation of Momentum 
             
     Substituting values 
             
Multiplying through by 
            
making 
 subject of the equation 2
             
Substituting this into equation 1
          
          
           
           
Multiplying through by 
           
             
             