Investigating terminal velocity

In summary, the conversation discusses instructions for finding the terminal velocity of an object falling through the air. The instructions involve recording the mass and dimensions of the object, timing its fall from various heights, and plotting graphs to estimate the terminal velocity. Different methods are suggested, including finding average speed and using a mathematical model.
  • #1
MBBphys
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Homework Statement


So, we were given these instructions to find the terminal velocity reached by an object falling through the air:
Equipment: bun-case; access to balance; calipers; metre rule; stopwatch.

Instructions:

1. Record the mass of the bun-case
2. Measure with a recorded precision the dimensions of the bun-case and draw a scale diagram of it.
3. Drop the bun case from approximately 1m above the ground and observe its fall.
4. Plan a method to time the fall of the bun case as accurately as possible.
5. Time the descent of the bun-case from 1m and then in increments up to a maximum of 2m to give sufficient data for analysis.
6. Plot a graph of time against height of drop
7. Plot a graph of average speed against height of drop

8. Use these graphs to estimate the terminal velocity and give your reasoning.

But how do we do that?

Homework Equations


(N/A)

The Attempt at a Solution


So, if you find the average speed (height/time) for each height at which you dropped it, eventually the average speed will plateau on the graph, equalling the terminal velocity?

Or is there a different reason? Thank you!
 
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  • #2
MBBphys said:
So, if you find the average speed (height/time) for each height at which you dropped it, eventually the average speed will plateau on the graph, equalling the terminal velocity?
It probably won't reach that plateau in this test, but maybe you can estimate where the plateau would be. Not sure if it is intended here, but that could involve having a mathematical model for how the velocity varies during the descent (based on theory) and fitting it to the data.
Another approach does not involve finding average velocities, so again may not be what is sought. When you drop it from 1.1m, the first 1m should be exactly like the descent from 1m. What does that suggest?
 

1. What is terminal velocity?

Terminal velocity is the maximum speed that an object can reach when falling through a fluid (such as air or water). It occurs when the force of gravity pulling the object down is equal to the force of air resistance pushing against it.

2. How is terminal velocity calculated?

Terminal velocity can be calculated using the formula v = √(2mg/pAC). Where v is the terminal velocity, m is the mass of the object, g is the acceleration due to gravity, p is the density of the fluid, A is the cross-sectional area of the object, and C is the drag coefficient.

3. What factors affect terminal velocity?

The factors that affect terminal velocity include the mass and shape of the object, the density and viscosity of the fluid, and the altitude or air pressure. These factors can change the balance between gravity and air resistance, resulting in a change in the terminal velocity.

4. How is terminal velocity investigated in experiments?

Terminal velocity can be investigated in experiments by dropping objects of different masses and shapes from a height and measuring their speed as they fall. The data can then be used to calculate the terminal velocity and determine how different factors affect it.

5. What are the real-world applications of studying terminal velocity?

Studying terminal velocity has many real-world applications, such as in designing parachutes and airbags that can safely slow down a falling object, understanding the behavior of objects in free fall (like skydivers), and in weather forecasting where air resistance plays a role in the movement of clouds and precipitation.

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