Answer:

Step-by-step explanation:
The acceleration of an object is the rate of change of the velocity of the object.
It is a vector quantity, so it has a magnitude and a direction.
The acceleration is given by:

where
is the final velocity
is the initial velocity
t is the time taken for the velocity to change
If the acceleration is positive, the direction is the same as the initial velocity; if the acceleration is negative, the direction is opposite to the initial velocity.
In this problem:
is the initial velocity
is the final velocity
t = 3 s is the time
So, the acceleration is
