Given data
*The given height is h = 3.1 m
*The value of the acceleration due to gravity is g = 9.8 m/s^2
The formula for the impact velocity is given by using the conservation of energy as
[tex]\begin{gathered} \frac{1}{2}mv^2=mgh \\ v=\sqrt[]{2gh} \end{gathered}[/tex]Substitute the known values in the above expression as
[tex]\begin{gathered} v=\sqrt[]{2\times9.8\times3.1} \\ =7.79\text{ m} \\ \approx7.8\text{ m} \end{gathered}[/tex]Hence, the impact velocity is v = 7.8 m/s and the correct option is (D)
