The centripetal acceleration of a particle moving at constant speed v over a circular trajectory with radius r is:
[tex]a_c=\frac{v^2}{r}[/tex]Replace v=5.6 m/s and r=65 m to find the centripetal acceleration:
[tex]\begin{gathered} a_c=\frac{(5.6\frac{m}{s})^2}{(65m)} \\ =\frac{31.36\frac{m^2}{s^2}}{65m} \\ =0.48246\ldots\frac{m}{s^2} \\ \approx0.48\frac{m}{s^2} \end{gathered}[/tex]Therefore, the runner's centripetal acceleration is 0.48 m/s^2
