A long steel wire of length 'L' and radius ‘r’ is suspended from the ceiling of a room. A sphere of mass 'm' and radius 'r1 ' is attached to the lower end of the wire. the height of the ceiling is (L+2r1+l) . When the sphere is made to oscillate as a pendulum, its lowest point just touches the floor. The velocity of the sphere at the lowest point will be ( L>>(r1 ,l ) )