There's kinetic and potential energy, and they need to be added to give the mechanical energy:
K = 1/2*m*v^2 = 1/2*0.25*30^2 = 112.5 J
U = mgh = 0.25*10*1.2 = 3J (notice that I took g = 10 m/s^2, instead of 9.81 ..., also I have assumed the common choice of U = 0 at the ground level (h=0), although what really matters are differences in height.
Total = 115.5 J.
