Simple kinematics question -- dropping a stone down a well

In summary, the boy dropped a 0.10 kg stone down a 150 m well and listened for the echo. Using the equations v = d/t and v2 = v2 + 2ax, they found that it took 5.53 seconds for the stone to reach the end of the well and .437 seconds for the sound to travel back, resulting in a total time of 6 seconds. The answer is correct when rounded to significant figures.
  • #1
Mr Davis 97
1,462
44

Homework Statement


[/B]
A boy drops a 0.10 kg stone down a 150 m well and listens for the echo. If the speed of sound is 343 degrees Celsius, the how long after the stone is dropped will the boy hear the echo?

Homework Equations



v = d/t

v2 = v2 + 2ax

The Attempt at a Solution


[/B]
What I did was use v2 = v2 + 2ax to find the velocity of the rock at the end of the well. Then I used v = at to find how long it takes to go from zero to that final velocity. Therefore, I found that the time it took to get to the end of the well was 5.53 s. Next I used t = d / v to find how long it took the sound to travel back, which is .437 s. Thus, adding these together, I got 6 s, rounded to sig figs. Is this answer correct?
 
Physics news on Phys.org
  • #2
Looks good to me.
 
  • Like
Likes Mr Davis 97

1. How long does it take for the stone to reach the bottom of the well?

The time it takes for an object to fall a certain distance is determined by the equation: t = √(2h/g), where t is time, h is height, and g is the acceleration due to gravity (9.8 m/s²). In this case, h would be the depth of the well. So, to find the time it takes for the stone to reach the bottom of the well, we need to know the depth of the well.

2. What is the velocity of the stone when it reaches the bottom of the well?

The velocity of the stone at the bottom of the well can be found using the equation: v = √(2gh), where v is velocity, g is the acceleration due to gravity, and h is the depth of the well. So, to find the velocity of the stone, we need to know the depth of the well.

3. Does the mass of the stone affect the time it takes to reach the bottom of the well?

No, the mass of the stone does not affect the time it takes to reach the bottom of the well. The time it takes for an object to fall a certain distance is only dependent on the height and acceleration due to gravity. The mass of the object does not play a role in determining the time.

4. How does the depth of the well affect the velocity of the stone?

The depth of the well does affect the velocity of the stone. As the depth increases, the velocity also increases. This is because the deeper the well, the longer the stone has to accelerate due to gravity. The equation for calculating velocity takes into account both the acceleration due to gravity and the depth of the well.

5. What factors can affect the accuracy of the calculated time and velocity?

The accuracy of the calculated time and velocity can be affected by a few factors. These include air resistance, the shape and size of the stone, and the precision of the measurements taken (e.g. depth of the well). Additionally, factors such as the Earth's rotation and air density can also have a minor impact on the results. In order to get more accurate results, it is important to minimize these factors as much as possible and perform multiple trials to get an average value.

Similar threads

Stone launched upward - Kinematics question
    • Introductory Physics Homework Help
Replies
11
Views
2K
Kinematics/speed of sound question
    • Introductory Physics Homework Help
Replies
3
Views
3K
Kinematics: falling stone question
    • Introductory Physics Homework Help
Replies
13
Views
10K
Calculate Time for Stone to Hit Bottom of 180m Well at 20C
    • Introductory Physics Homework Help
Replies
9
Views
1K
Kinematics: find maximum height
    • Introductory Physics Homework Help
Replies
2
Views
3K
Calculating Charge Of Electron (Millikan Oil Drop Experiment
    • Introductory Physics Homework Help
Replies
1
Views
2K
Kinematics on a frictionless incline plane
    • Introductory Physics Homework Help
Replies
3
Views
1K
Depth of a well (using speed of sound)
    • Introductory Physics Homework Help
Replies
6
Views
2K
Calculating the Depth of a Well and Velocity of a Rock Using Equations of Motion
    • Introductory Physics Homework Help
Replies
3
Views
1K
Kinematics question, easier way to do this?
    • Introductory Physics Homework Help
Replies
6
Views
2K

Hot Threads

Recent Insights

Back
Top