Answer: -39.2 m/s directed downwards
Explanation:
We can solve this problem with the following equation:
[tex]V=V_{o}+gt[/tex]
Where:
[tex]V[/tex] is the ball's velocity at 4 s
[tex]V_{o}=0m/s[/tex] is the ball's intial velocity, since it was dropped from rest
[tex]g=-9.8 m/s^{2}[/tex] is the acceleration due gravity, aways directed downwards
[tex]t=4 s[/tex] is the time
Solving:
[tex]V=0m/s-9.8 m/s^{2}(4 s)[/tex]
Finally:
[tex]V=-39.2 m/s[/tex] The negative sign indicates the velocity is downwards
