The time will be 0.9 sec
According to the question
Distance apple will cover = 4 m
Gravitational acceleration = 9.8 m/s2
As we know
[tex]S=1/2 at^2[/tex]
In vertical direction a = g
By rearranging
[tex]T = \sqrt{(2s/g)}[/tex]
[tex]Time = \sqrt{(2 * 4/9.8)}[/tex]
[tex]Time = 0.9 sec[/tex]
So, apple will take the time of 0.9s