Answer
$a\approx3.09m/s^{2}$
Work Step by Step
We first convert the velocity into meters per second:
$60km/h\times\frac{1000m}{1km}\times\frac{1h}{3600s}\approx16.7m/s$
We know the following equation:
$a=\frac{\Delta v}{t}$
We plug in the known values to obtain:
$=\frac{16.7m/s}{5.4s}\approx3.09m/s^{2}$
