Given that,
Let initial speed of the piece of wood, u = 0
Finally, it reaches to a speed of 68.6 m/s. It will be its final velocity. We need to find the time taken by it to fall. Using equation of motion as :
[tex]v=u+at[/tex]
a = g
[tex]v=gt\\\\t=\dfrac{v}{g}\\\\t=\dfrac{68.6}{9.8}\\\\t=7\ s[/tex]
So, it will taken 7 seconds to fall. Hence, this is the required solution.
