This question was well understood and also well attempted by most candidates as they were able to use the relation w = ½ ke2 correctly. However, very few use wrong formula. That is w = ½ ke and arithmetic blunder thus = 55.06 – 55 = 0.6.Instead of 0.06
The expected solution is
Work done = ½ Ke2
= ½ x 700 x (55.06 – 55)2
= 1.26 J