Answers

2016-04-08T00:37:29+05:30
900 J.
Let the stiffness constant of the spring be k
Therefore, the elastic potential energy stored by the spring when it is stretched through a distance of 'a' from its natural length = (1/2) X k X a X a = 25 J (given).
So, k X a X a = 50 J
Now, the total elastic potential energy stored by the spring when it is stretched through an additional distance of '5a' that is the total distance of '6a' from its natural length = (1/2) X k X 6a X 6 
                                                            =  18 X k X a X a
                                                            =  18 X 50 J
                                                            =  900 J 
 
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