The displacement of a particle executing simple harmonic motion is $y=A \sin (2 t+\phi) \mathrm{m}$, where $t$ is time in second and $\phi$ is phase angle. At time $t=0$, the displacement and velocity of the particle are 2 m and $4 \mathrm{~ms}^{-1}$. The phase angle, $\phi=$

The displacement of a damped oscillator is $x(t)=\exp (-0.2 t) \cos (3.2 t+\phi)$, where $t$ is time in second The time requirement for the amplitude of the oscillator to become $\frac{1}{e^{1.2}}$ times its initial amplitude is

Time period of a simple pendulum in air is $T$. If the pendulum is in water and executes SHM. Its time period is $t$. The value of $\frac{T}{t}$ is. (density of bob is $\frac{5000}{3} \mathrm{~kg} \mathrm{~m}^{-3}$ )

For a particle executing simple harmonic motion, Match the following statements ( conditions) from Column I to statements (shapes of graph) in Columinit

Column I	Column II
a Velocity-displacement graph $(\omega=1)$	i Straight line
b Acceleration-displacement graph	ii Sinusoidal
c Acceleration - time graph	iii Circle
d Acceleration - velocity $(\omega \neq 1)$	iv Ellipse