Question

A stone is dropped from the top of a cliff. It is seem to hit the ground below after 4.2 sec. How high is the cliff ?

a. 84.44m
b. 860m
c. 160m
d. -180m

Answer 1

To calculate the height of the cliff, use the equation for the distance an object travels when dropped, with a runtime of 4.2 seconds. The height of the cliff is approximately 86 meters.

Step-by-step explanation:

To calculate the height of the cliff, we can use the equation for the distance an object travels when dropped:

distance = (1/2) * acceleration due to gravity * time^2

Since the stone is dropped, the initial velocity is 0, so we can simplify the equation to:

distance = (1/2) * 9.8 m/s^2 * (4.2 sec)^2

Solving for distance, we get:

distance = 0.5 * 9.8 m/s^2 * 17.64 sec^2 = 86.148 m

Therefore, the height of the cliff is approximately 86 meters, which corresponds to option b.