A stone is dropped from the top of a cliff. It is seen to hit the ground below after 3.90 s. How high is the cliff?

Use Equations of Kinematics

u = initial velocity = 0
S = distance travelled in metres
t = time in seconds
g = acceleration due to gravity = -9.81 m/s²

S = ut + (1/2)gt²
Solve for S.

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A stone is dropped from the top of a cliff. The splash it makes when striking the water below is heard 4.5 s later.

To calculate the height of the cliff, we need to use the formula for free fall motion:

h = (1/2) * g * t^2

where:
h = height of the cliff
g = acceleration due to gravity (which is approximately 9.8 m/s^2 on Earth)
t = time taken for the stone to reach the ground (which is given as 3.90 s)

Substituting the given values into the formula:

h = (1/2) * 9.8 * (3.90)^2
h = 4.9 * 3.90^2
h = 4.9 * 15.21
h ≈ 74.67 meters

Therefore, the height of the cliff is approximately 74.67 meters.