An object travels 8 meters in the 1st second of travel, 8 meters again during the 2nd second of travel, and 8 meters again during the 3rd second. Its acceleration is

0 m/s^2

Explanation:

Use a formula to answer the question

d = r * t

The object is not changing speed at any time, or if it is we are not told.  The rate is the speed.

8 = r * 1 second

8 m/sec = r

The initial speed is 8 and the final rate is 8. There is no change. So when you use this formula

a = (vf - vi)/t we get a = (8 - 8)/1 = 0

There is no acceleration because there is no change in speed.