A body is executing SHM. When its displacements from the mean position are $$4 \mathrm{~cm}$$ and $$5 \mathrm{~cm}$$ it has velocity $$10 \mathrm{~cms}^{-1}$$ and $$8 \mathrm{~cms}^{-1}$$ respectively. Its periodic time $$\mathrm{t}$$ is

A particle executes a simple harmonic motion of amplitude $$\mathrm{A}$$. The distance from the mean position at which its kinetic energy is equal to its potential energy is

The phase difference between displacement and velocity of a particle in simple harmonic motion is

A particle is performing simple harmonic motion. Equation of its motion is $$x = 5\sin \left( {4t - {\pi \over 6}} \right),x$$ being the displacement from mean position. Velocity (in ms$$^{-1}$$) of the particle at the instant when its displacement is 3, will be