Key: object is thrown upward. When it reaches the highest point, the velocity is 0. The whole journey is divided into 2 parts: upward - highest point - downward to hit the ground. 2 parts have different displacement (and different time). 
If an object is thrown straight upward with an initial speed of 8 m/s and takes 3 seconds to strike the ground, from what height was the object thrown?  $\textasciitilde$  $\textasciitilde$  $\textasciitilde$  $\textasciitilde$ 
Options:
(1) $$24.2m$$ 
(2) $$21m$$ 
(3) $$23m$$ 
(4) $$2.3m$$ 
(5) $$69m$$ 