Answer:
The time is 4 sec.
Step-by-step explanation:
Given that,
Distance = 78.4 m
We need to calculate the time
Using equation of motion
\(s=ut+\dfrac{1}{2}gt^2\)
\(t =\sqrt{\dfrac{2s}{g}}\)
Where, s = distance
g = acceleration due to gravity
t = time
\(t =\sqrt{\dfrac{2\times78.4}{9.8}}\)
\(t=4\ sec\)
Hence, The time is 4 sec.
