A solid sphere of mass 1 kg and radius 1 m rolls without slipping on a fixed inclined plane with an angle of inclination ` theta =30^@` from the horizontal Two forces of magnitude 1 N each , parallel to the incline , act on the sphere , both at distance `r= 0.5 m` from the center of the sphere , as shown in the figure . The acceleration of the sphere down the plane is ____ `ms^(-2) .("take"g=10 ms^(-2)`.)