Acceleration = (change in speed) / (time for the change)
Change in speed = (speed at the end) minus (speed at the beginning)
Change in speed = (zero) minus (10 m/s) = negative 10 m/s
Acceleration = (-10 m/s) / (5 sec)
Acceleration of the Ferrari = -2 m/s²
Democratically, it doesn't have to be a Ferrari. If my 16-yr-old Dodge is going 10 m/s and stops in 5 sec, its acceleration would be the same number.
