Question #f7702

1 Answer
Sep 25, 2017

4 sec

Explanation:

Time in free falling t=8 sec
after 8 sec the body touches the ground.
Initial velocity is zero.
Initial Velocity u=0
Acceleration a=g

Using Newton's second equation of Motion
s=ut+1/2at^2
first we find total distance h

h=0+1/2(9.8)8^2=313.6 m
Hence
h/4=313.6/4=78.4m

time taken to travel distance 78.4m
78.4=0+1/2(9.8)t^2
9.8t^2=156.8
t^2=16
t=4 sec