There are several many equations that are available to relate the distance,
speed, and time of a body moving vertically in gravity. Happily, the only one
I can always remember without looking it up happens to be the right one to
use for this question !
       Distance = (1/2) x (gravity) x (time)²
          3.8 m = (1/2) x (9.8 m/s²) x (time)²
Divide each side
by 4.9 m/s² :
          (3.8 m) / (4.9 m/sec²) = (time)²
           0.7755 sec² = time²
Square root
of each side:
            0.88 second = time
