Adriver starts his parked car and within 5 seconds reaches a speed of 60km/h, as he travels east. what is his acceleration?

Acceleration  = 
(change in speed) / (time for the change)
               and the direction of the change.

Acceleration  =  (60 - 0) km per hour / 5 sec  =  12 km per hour per second, east.

I hear teachers all over the country complaining about that ugly unit.
It has to be changed to a more familiar unit of acceleration.

(12 km/hour) x (1 hour/3600sec) = 12,000/3600 = 3-1/3 meter/sec.

His acceleration is  3-1/3 meters per second² .