A car moving on a straight road accelerates from a speed 5.1m/s to a speed of 7.9m/s in 3S. What is its average acceleration?

Initial velocity  $u=5.1m/s$
Final velocity  $V=7.9m/s$
Time taken  $t=3S$
$\therefore$ Average acceleration  $a=\frac{V-u}{t}$
                                          $\begin{array}{l}=\frac{7.9-5.1}{3}\\ =\frac{2.8}{3}=0.93\mathrm{m}/{\mathrm{s}}^2\end{array}$