Answer:
t = 0.553
Step-by-step explanation:
The mass has nothing to do with an object falling.
Givens
d = 1.5 m
a = 9.8
vi = 0
t = ?
Formula
d = vi * t + 1/2 a t^2
Solution
1.5 = 0 + 1/2 9.81 * t^2
1.5 = 4.905 t^2
1.5/4.905 = t^2
0.3058 = t^2
sqrt(t^2) = sqrt(0.3058)
t = 0.553
About 1/2 a second which is really surprising wouldn't you think?