You drop a stone down a well that is 9.5 m deep. How long is it before you hear the splash? The speed of sound in air is 343 m/s and air resistance is negligible.
A) 1.3 s
B) 1.4 s
C) 1.6 s
D) 1.5 s
E) 1.2 s

Question

Quizplus · Accepted Answer

To solve this, we first find the time it takes for the stone to fall using the equation $d = \frac{1}{2}gt^2$, where $d$ is the depth of the well (9.5 m) and $g$ is the acceleration due to gravity (approximately $9.8 m/s^2$). Solving for $t$, we get $t = \sqrt{\frac{2d}{g}} = \sqrt{\frac{2*9.5}{9.8}} \approx 1.39$ seconds. Then, we calculate the time it takes for the sound to travel back up the well using the equation $t = \frac{d}{v}$, where $d$ is again the depth of the well and $v$ is the speed of sound (343 m/s). This gives $t = \frac{9.5}{343} \approx 0.028$ seconds. Adding these two times gives a total of approximately $1.39 + 0.028 \approx 1.418$ seconds, which rounds to 1.4 seconds.

You Drop a Stone Down a Well That Is 9