Answer:
0.45 s.
Explanation:
From Newton's equation of motion,
s = ut + 1/2gt²........................ Equation 1
Where s = distance, u = initial velocity, a = acceleration, t = time
Given: s = 1.0 m, u = 0 m/s (dropped from height), g = 9.81 m/s²
Substituting into equation 1,
1 = 0(t) + 1/29.81(t²)
1 = 9.81t²/2
2 = 9.81t²
t² = 2/9.81
t² = 0.204
t = √(0.204)
t = 0.45 s.
Hence it takes 0.45 s for the book to reach the elevator floor.