Two simple harmonic motions are represented by the equations $y_1 = 0.1 \sin (100 \pi t + \frac{\pi}{3} )$ and $y_2 = 0.1 \cos \pi t$. The phase difference of the velocity of particle 1, with respect to the velocity of particle 2 is :

Question

( A ) $\frac{-\pi}{6}$
( B ) $\frac{-\pi}{3}$
( C ) $\frac{\pi}{3}$
( D ) $\frac{\pi}{6}$