Question

A boy finds an abandoned mine shaft in the woods, and wants to know how deep the hole is. He drops in a stone, and counts 4 seconds before he hears the "plunk" of the stone hitting the bottom of the shaft. Approximately how deep is the shaft? (Assume a gravitational acceleration of 9.8 m/s2 and no significant air resistance.)
A. 14 meters
B. 24 meters
C. 39 meters
D. 78 meters

Answer 1

The shaft is 78m approximately deep. The correct option is D which is 78 meters

What are Sound Waves ?

Sound waves are longitudinal. That is, the direction of the waves is parallel to the direction of its propagation of particles.

Given that a boy finds an abandoned mine shaft in the woods, and wants to know how deep the hole is. He drops in a stone, and counts 4 seconds before he hears the "plunk" of the stone hitting the bottom of the shaft.

• The speed of the sound V = 330m/s

• The time it takes the sound to reach the top = t

Speed V = distance / time

330 = h/t

Make t the subject of formula

t = h/330

As the stone is dropped, initial velocity = 0, Using the formula

h = 1/2gT²

But T = 4 - t

T = 4 approximately

Substitute all the parameters

h = 1/2 × 9.8 × (4)²

h = 4.9 × (16)

h = 78.4m

Therefore, the shaft is 78m approximately deep. The correct option is D which is 78 meters

Learn more about sound wave here: https://brainly.com/question/16093793

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