Answer :
Time taken to reach water :
[tex]t = \dfrac{D}{v}\\\\t=\dfrac{6.78}{8.06}\ s\\\\t=0.84\ s[/tex]
Now, initial vertical speed , u = 0 m/s.
By equation of motion :
[tex]h = ut +\dfrac{at^2}{2}[/tex]
Here, a = g = acceleration due to gravity = 9.8 m/s².
So,
[tex]h = 0(t) +\dfrac{9.8\times 0.84^2}{2}\\\\h=3.46\ m[/tex]
Therefore, the height of the bridge is 3.46 m.
Hence, this is the required solution.