To find the time it takes for an object to fall from rest and hit the ground, we can use the equation for free fall motion:
h = (1/2)gt^2
where h is the height, g is the acceleration due to gravity, and t is the time.
Given that the height of the building is 1200 cm, we need to convert it to meters:
h = 1200 cm = 12 meters
The acceleration due to gravity near the surface of the Earth is approximately 9.8 m/s^2.
Plugging in the values into the equation, we get:
12 = (1/2)(9.8)t^2
Rearranging the equation to solve for t, we have:
t^2 = (2 * 12) / 9.8
t^2 = 24 / 9.8
t^2 ≈ 2.45
Taking the square root of both sides, we find:
t ≈ √2.45
t ≈ 1.57 seconds
Therefore, it will take approximately 1.57 seconds for the object to hit the ground when dropped from rest from the top of a 1200 cm building.