How can you Calculate the Reaction Time from the Ruler Drop Experiment?

-Since the Acceleration will be Constant - 10 [Earth's GFS] we can find the Reaction Time -If Person 1 caught the Ruler at 20 cm, we can use this Formula to Proceed: v² - u² = 2 x a x d. u² = 0 because it started on 0 Speed. a = 10 because Earth's GFS. d = 20cm because that's how Far the Ruler Dropped. v = Change in Speed. v² = 2 x 10 x 0.2 [20 cm = 0.2 meters] so v² = 4 so v = 2. -And now Finally, Acceleration = Change in V / Time -10 = 2 / t so t = 2/10 so Reaction Time = 0.2s