According to second equation of motion
S = Vi t + 1/2 at² ( where Vi= initial velocity , t= time ,a= acceleration,)
Before starting the motion object is at rest so initial velocity =Vi = 0
As object is falling freely so it posses
acceleration due to gravity = g =10 m/sec² (a =g)
time =t= 6.0 s
Putting values of a=g ,, t and Vi in second equation of motion.
S= (0)(6.0s) + 1/2 (10m/s²) (6.0s)²
= 0 + 1/2 ( 10m/s²)(36s²)
S = 180m