
Explanation:
Area is pi×r^2 and you times it by the fraction of the circle you have as its not a full circle.
The square root of pi is 1.77245385091.
Answer:
2.83 s
Step-by-step explanation:
We are given that

When a rock reached the ground then h(t)=0


Using quadratic formula





Time cannot be negative .Therefore, negative value of t can not be possible.
Hence, the rock takes 2.83 sec to reach the ground.