Question

Wondering if you have enough rope to rappel to the ground, you drop a rock off the top, and hear the sound of it hitting the bottom 4.2 seconds later. Find the height of the cliff ignoring the time that the sound takes to travel back to you from the bottom.

Answer 1

86.5 m

Step-by-step explanation:

Answer 2

86.5 m

Step-by-step explanation:

`s = ut + (1)/(2) at {}^(2) \\ s = (0)(4.2) + (1)/(2) (9.81)(4.2) {}^(2) \\ s = 86.5m`