A body of mass 1kg executing S.H.M., its displacement y cm at t seconds is given  by  $y=6\sin \pi \left(\frac{100}{\pi }t+\raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$4$}\right.\right)$. Its maximum kinetic energy is 

For a body executing simple harmonic motion the maximum kinetic energy will  be  at its mean position. We know that,
Mechanical energy = Potential Energy + Kinetic energy
At mean position potential energy is 0. Hence the mechanical energy will be  equal  to maximum kinetic energy.
Mechanical energy = $\frac{1}{2}m{\omega }^2{A}^2$  
Where m=1kg, $\omega =100rad/s$ , A=0.06m
Substituting this in the relation for maximum kinetic energy i.e. mechanical energy,  we get
ME =  $\frac{1}{2}\left(1\times {100}^2\times {0.06}^2\right)$
Hence ME =  $\frac{1}{2}\left(36\right)=18J$.