The acceleration due to gravity on planet X is one fifth that on the surface of the earth.?
If it takes 3.4 s 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?
Answer in units of s.
Answer by question
Falls from rest means that the starting velocity is 0, right? That means the equation used can be
x = 1/2 a t^2
and on earth, it’s 1/2 g (3.4)^2. The distance is the same, so I can set Earth’s equation equal to planet X’s equation:
1/2 g (3.4)^2 = 1/2 g/5 t^2
and then I solve for t:
sqrt(5*3.4^2) = t on planet X, and because my initial unit was s, my unit now is also s. I don’t know what that is, though, so you’ll have to use a calculator. Sorry 
Add your own answer in the comments!
H=1/2 g t² H = 1/2* 9.81 * 3.4² H = 56.70 m
On the Planet X
H= 1/2 gx tx² tx=√(2H/gx) = √(113.4 / 9.81/5)=√57.80 = 7.6 Sec
Where tx is the time to fall on the Planet X and gx = g/5 of the earth