Two particles are oscillating along two close parallel straight lines side by side, with the same frequency and amplitudes. They pass each other, moving in opposite directions when their displacement is half of the amplitude. The mean positions of the two particles lie on a straight line perpendicular to the paths of the two particles. The phase difference is

Out of the following functions representing motion of a particle which represents SHM
(1)  y = sin$$\omega $$t $$-$$ cos$$\omega $$t
(2)  y = sin³$$\omega $$t
(3)  y = 5cos$$\left( {{{3\pi } \over 4} - 3\omega t} \right)$$
(4)  y = 1 + $$\omega $$t + $$\omega $$²t²

The period of oscillation of a mass M suspended from a strong of negligible mass is T. If along with it another mass M is also suspended, the period of oscillation will now be

The displacement of a particle along the x-axis is given by x = asin²$$\omega $$t. The motion of the particle corresponds to