Question

A boulder falls off the top of a cliff during a storm. The cliff is 90 feet high.

Answer 1

Answer:

It will take the boulder approximately 4.28 seconds to hit the road

Step-by-step explanation:

The given height of the cliff from which the boulder falls, h = 90 feet

The equation that can be used to find the time it takes the boulder to fall is h = u·t + (1/2)·g·t²

Where;

h = The height of the cliff = 90 ft.

u = The initial velocity of the boulder = 0 m/s (The boulder is assumed to be at rest when it falls)

g - The acceleration due to gravity ≈ 9.81 m/s²

t = How long it will take for the boulder to hit the road below

Plugging in the values gives;

90 = 0 × t + (1/2)×9.81×t² = 4.905·t²

∴ t = √(90/4.905) ≈ 4.28

The time it takes the boulder to hit the road, t ≈ 4.28 seconds.