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.

air exerts forces on falling objects near earth’s surface.

explanation:

the term 'free falls' refer to object that are falling towards the earth, in a situation in which gravity is the only force acting on the object.

for an object in free fall, the acceleration is constant (g, the gravitational acceleration), and so the velocity of the object constantly increases.

for objects near earth's surface, there is always another force acting on the object: the resistance due to the air. this force is opposed to the direction of fall of the object, and it is proportional to the velocity of the object, so as the object falls down, this force increases up to a point when it balances the force of gravity, and the object continues its motion at constant velocity (called terminal velocity). since in this case gravity is not the only force acting on the object, we are not in a situation of free fall.