Stone in a Well Problem
Unit: 1D Kinematics
Prerequisites
Later Topics
Multi-Step Problem Preview
Part 1 of 4 — sign up to solve the full problem!
Part 1
A stone is dropped into a well of unknown depth meters.
We hear the sound of the splash after .
Our goal is to calculate how deep the well is. The speed of sound is .
Solve for the time that it takes the stone to hit the bottom of the well. Write your answer in terms of and .
Correct!
To find the time it takes for the stone to fall to the bottom of the well, we use the kinematic equation for an object in free fall under constant acceleration. Let's define the downward direction as positive. The displacement of the stone is the depth of the well, . The stone is dropped, so its initial velocity is . The acceleration is the acceleration due to gravity, .
The kinematic equation for displacement is:
Substituting the known values for the stone's fall:
Now, we can solve this equation for the time, . First, multiply both sides by 2 and divide by :
Finally, take the square root of both sides to get the expression for :
Want to solve all 4 parts?
Sign up for a free account to work through the complete multi-step problem with instant feedback!
Ready to Start Learning?
Sign up now to access the full Stone in a Well Problem lesson and our entire curriculum!