Answer:
2.04 seconds
Step-by-step explanation:
Falling objects near the surface of the earth have an acceleration of -9.81 m/s².
Acceleration is the change in velocity over change in time:
a = (v − v₀) / t
-9.81 = (-30.0 − (-10.0)) / t
-9.81 = -20.0 / t
t = 2.04
It takes 2.04 seconds.
