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