Answer:
50 J
Step-by-step explanation:
According to energy conservative law energy can not be destroyed. So as the potential energy has been decreased to 50 J, the decreased amount has become kinetic energy. 
 100 - 50 = 50
 
 
        
             
        
        
        
This is 1:25 (C) 
Explanation:
        
             
        
        
        
It would be 61180 because u need to multiply 3059x20 =61180