Answer:
h = 38.41 m
Explanation:
Given that,
A ball is thrown horizontally from the top of a building and strikes the sidewalk after 2.8 s.
We need to find the height of the building. Let it is h.
Initial speed of the ball, u = 0
Using second equation of motion to find h as follows :
[tex]h=ut+\dfrac{1}{2}at^2\\\\\text{Put u = 0 and a = g}\\\\h=\dfrac{1}{2}gt^2\\\\=\dfrac{1}{2}\times 9.8\times 2.8^2\\\\=38.41\ m[/tex]
So, the building is 38.41 m tall.