The acceleration due to gravity on planet x is one fifth that on the surface of the earth. if it takes 3.5s for an object to fall a certain distance from rest on earth, how long would it take to fall the same distance on planet x?

The distance traveled by a drop object (free fall) is calculated through,
                                   d = 0.5gt²
Since the acceleration due to gravity of Planet X is 1/5 that of Earth's, falling to same distance will give as a ratio and proportion of,
                (d1/d2) = 1 = (0.5)(9.8 m/s²)(3.5 s)² / (0.5)(1.96 m/s²)(t²)
The value of d in the equation above is 7.83 s. Thus, it will take for the same object 7.83 s to reach the ground. 

Answer8.0m;