Answer:
t = 10 s
Step-by-step explanation:
Given :
Altitude, h = 490 m
Initial velocity of a plane, u = 250 m/s
To find :
The time required for the packet to hit the ground. When it hits the ground its velocity will be 0. Let t is the required time. It can be calculated as follows :
![t=\sqrt{(2h)/(g)} \\\\t=\sqrt{(2* 490)/(9.8)} \\\\t=10\ s](https://img.qammunity.org/2021/formulas/physics/high-school/jun685u3jycehwaxzvtx6sn1dedt02qdxr.png)
So, it will take 10 s to reach the ground.