The calculation determines the time for an object to fall from a given height under gravity. Using the free fall equation without initial velocity,
h =
1⁄
2 gt2, where:
- h represents height (45 m)
- g represents the acceleration due to gravity (9.8 m/s2)
- t is the time in seconds
Substituting the given values: 45 m =
1⁄
2 (9.8 m/s
2)
t2. Solving for
t2: 45 m = 4.9
t2, which leads to
t2 =
45 m⁄
4.9 m/s2, resulting in
t2 = 9.18. Therefore,
t ≈ √9.18 ≈ 3.03 s.
Rounded to the nearest second, t ≈ 3 s.
The time for the object to reach the ground is approximately 3 seconds. The correct answer is 3 s.