Answer:
The height of the platform is 22.686 m.
Step-by-step explanation:
Given;
initial velocity of Janet, u = 2.63 m/s
time of her motion, t = 1.9 s
The height of the platform is given by;
h = ut + ¹/₂gt²
substitute the given values and solve for height "h"
h = (2.63 x 1.9) + ¹/₂(9.8)(1.9)²
h = 4.997 + 17.689
h = 22.686 m
Therefore, the height of the platform is 22.686 m.