Answer: 1.42 sec
Step-by-step explanation:
The object is dropped from the height. So initial velocity, u = 0 m/s.
Height = 10m and Acceleration = g = 9.8 m/s² (or g can be approximated to 10 m/s²)
Using the Second equation of motion;
s = ut + (1/2) at²
~ 10 = 0 + (1/2) gt²
~ t² = 20/9.8 = 100/49
~ t = 10/7 seconds = 1.42 seconds