Assuming Usain Bolt starts from rest (so, its initial velocity is zero), and that his motion is uniformly accelerated, his position at time t is given by [tex]S(t) = \frac{1}{2}at^2 [/tex] where a is the average acceleration and t the time. In our problem, the distance covered is S=100 m and the time taken is t=9.58 s, therefore the average acceleration can be found by re-arranging the previous formula: [tex]a= \frac{2S}{t^2}= \frac{(2)(100 m)}{(9.58 s)^2}=2.18 m/s^2 [/tex]
