The potential energy of a particle is given by where a and b are constants. Mass of the particle is 1kg and x.y are the coordinates of the particle in meters. U is in joule. The particle is at rest at at time t = 0 (A) speed of the particle when it crosses x - axis is (B) speed of the particle when it crosses x - axis is (C) speed of the particle when it crosses y -axis is (D) co-ordinates of the particle at t=1 second are