Given,
A ball is thrown vertically upward from the ground at the speed of 34m/s.
At t he heighest position the velocity is zero.
Thus the time taken to reach the top is
[tex]\begin{gathered} v=u+gt \\ \Rightarrow0=34-9.8t \\ \Rightarrow t=3.46\text{ s} \end{gathered}[/tex]So to reach the group from the top it woukd require the same time.'
Thus total time required to reach the ground is
3.46s+3.46s=6.92s
The total time is 6.92 sec.
