Answer to Question #234921 in Physics for Potchie

Question

1. Jennie dropped a stone from the top of the blackpink house which is 400 m high.

1. How long will it take for the stone to reach the ground?

Answer 1

Given:

$H=400\:\rm m$

The time of free falling of the stone

$$t=\sqrt{2H/g}=\sqrt{2*400\:\rm m/9.8\:\rm m/s^2}=9.0\:\rm s$$