Acar traveling at 22 m/s starts to decelerate steadily. it comes to a complete stop in 7 seconds. what is its acceleration?

acceleration = -3.14285 m/sec²
The negative sign indicates a deceleration which means that the body is decreasing its velocity

Explanation:
To answer this question, we would use an equation of motion as follows:
V = U + at
where:
V is the final velocity = 0 m/sec (body comes to rest)
U is the initial velocity = 22 m/sec
a is the acceleration we want to find
t is the time = 7 sec

Substitute with the givens in the above equation to get the acceleration as follows:
V = U + at
0 = 22 + 7a
-22 = 7a
a = -22/7
a = -3.14285 m/sec²

The negative sign indicates a deceleration which means that the body is decreasing its velocity.

Hope this helps :)