Question

A 5 kg rock is dropped down a vertical mine shaft. How long does it take to reach the bottom, 79 meters below?

Answer 1

Answer:

The time for the rock to reach the bottom is 4.02 seconds.

Explanation:

Given;

mass of the rock, m = 5 kg

height of the rock fall, h = 79 meters

The time to drop to the given height is given by;

$t = \sqrt{\frac{2h}{g} }$

where;

t is the time to fall to the bottom

g is acceleration due to gravity = 9.8 m/s²

$t = \sqrt{\frac{2h}{g} } \\\\t = \sqrt{\frac{2*79}{9.8} }\\\\t = 4.02 \ s$

Therefore, the time for the rock to reach the bottom is 4.02 seconds.