A man throws a stone vertically down from a height with an initial velocity = -5 m / s . After 3 seconds , the stone reaches the ground ( at point A ) . What is the height h ?

Given:
The initial velocity of the stone, v₀=-5 m/s
The time it takes for the stone to reach the ground, t=3 s
To find:
The height.
Explanation:
From the equation of motion,
[tex]-h=v_0t-\frac{1}{2}gt^2[/tex]On substituting the known values,
[tex]\begin{gathered} -h=-5\times3-\frac{1}{2}\times9.8\times3^2 \\ \Rightarrow-h=-60 \\ \Rightarrow h=60\text{ m} \end{gathered}[/tex]Final answer:
The height from which the