Answer:
I think it is the forth one
The distance covered by the acorn is 3.136 m.
<u>Explanation:</u>
The time taken for the acorn to hit the ground is 0.8 s. As it is a free fall, the acorn will be completely under the influence of gravity. So the acceleration will be acceleration due to gravity.
Then using the second law of equation,

Since the initial velocity and time is zero, then the time taken to reach the ground is stated as 0.8 s, so

So the distance covered by the acorn is 3.136 m.
Given:-
- Speed of the unicycle = 20 m/s
- Time taken = 15 s
To Find: Distance travelled by the unicycle.
We know,
s = vt
where,
- s = Distance travelled,
- v = Speed &
- t = Time taken.
Therefore,
s = (20 m/s)(15 s)
→ s = (20 m)(15)
→ s = 300 m (Ans.)