The acceleration of the fire truck is 1.666 m/s².
<u>Step-by-step explanation:</u>
Acceleration is the measure of change in velocity with respect to time. So as the initial velocity of the fire truck is given as 0 km/hr and the final velocity is given as 66 km/hr. So at first the truck is at rest and on switching on the engine, the truck gets to the velocity of 66 km/hr in 11 seconds.
But first the units of velocity should be changed from km/hr to m/s
1 hour = 3600 seconds
1 km = 1000 m
So,
Converted Velocity = 18.33 m/s
Then, the acceleration will be
Acceleration = 1.666 m/s²
So, the acceleration of the fire truck is 1.666 m/s².