\( \theta \,\, = \,\, \frac{{25\,\, \times \,\,2\pi }}{{2\pi r}}\,\,rad\,\,\, = \,\,\frac{{25}}{{0.3}}\,\, = \,\,83\,\,rad \)
\( \omega \,\, = \,\,0\,,\,\,{\omega _0} = \,\,2\,\, \times \,\,2\pi \,\, = \,\,4\pi \,\,rad/s \)
\( \therefore \,\,\alpha \,\, = \,\,\frac{{{\omega ^2} - \omega _0^2}}{{2\theta }}\,\,\, = \,\,\,\frac{{{0^2} - {{(4\pi )}^2}}}{{2\,\, \times \,\,83}}\,\,\, = \,\, - 0.95\,\,rad\,\,{s^{ - 2}} \)