                       3 12a      m         4×104   44       u¹      104m\s  22000   \      
       
=½mu²1                                                             3 16 
 =½× 4×104 × 104 ²                                   3 17 
 =2×104×108                                                3 18 
 =2×1012                                                    3 19 
     10                                                         
     
    =2                                             3 20 
                                                                         R        6.37×106  3.9    3 15                  R      R   m¹      m =5.98×1024    m²     m =4×104                  G 6.67×10-11 
        
      Re
=                                                       3 21 
        Gmem
                       6.37×106
 =                                                       3 22 
         6.67×10 11 × 5.98×1024   × 4×104 
 = 2.5×1012                                                                            3 23 
 = 2.5                                                                             3 24 
    3 12        a                 b                    
                   
      
 =      ＋                                                                                               3 25 
 = ＋2.0 2.5                                                                                                       3  26 
 = 0.5                                                                                                                   3 27 
                                         
                                   3 12 b                                 R  R      2R                
    
           2
 =    ×2.5                                                   3 28 
          1
 = 1.25                                                                  3 29 
              
          0.5                                        3 30 
      
   
 =＋0.75                                                                   3 31 
            
  = ＋0.751.25 =0.5                
     u²           
    2
 mu² =0.75× 1017                                                                      3 32 
   1
     
u²=6.1×103m\s