Can You Measure Terminal Velocity in a Classroom Experiment?

[Monroe]

Homework Statement

I am putting forward this plan for discussion, in the hopes that it will be helpful for myself and others also doing this for their ocr physics A A2 levels.

The task is a planning exercise where you must write a plan for the investigation of Stokes' law.
I welcome the addition of new questions to this thread and discussion about this plan.
My particular questions about this, at this time is whether it is possible to measure terminal velocity of a ball baring in a class experiment? The problem i forsee in measuring this, is knowing when terminal velocity is actually reached, and recording this. The ball can be in air or any medium.

Homework Equations

Stokes law : F=6πrηv

F= the resistive force experienced by the sphere as it travels through the medium
r = radius of sphere
η = the coefficient of viscocity of the medium, which can be treated as a constant, unless the temperature or density of the medium changes.
v= the velocity of the sphere

When traveling at terminal velocity, the weight is balanced by the resistive force and upthrust, leading to the equation:

v = kr² where k can be considred as a constant,
such that k = 2(ρs - ρm)g / 9η

where ρs = density of sphere, and ρm = density of medium
g = gravity

The Attempt at a Solution

 

[kiwi3007]

http://www.ugrad.physics.mcgill.ca/labs/Reports/Sample1.htm

great site lots of info and ideas.

and it can really help you get your head around it if you don't get it.

 

[nlightner]

I appreciate the effort put into this plan for the investigation of Stokes' law. It is important to have a well-structured plan in order to conduct a successful experiment.

In response to your question about measuring terminal velocity of a ball bearing in a class experiment, it is definitely possible. However, as you mentioned, the challenge would be accurately determining when terminal velocity is reached and recording it. One way to address this issue is to use high-speed cameras to capture the motion of the ball bearing and analyze the footage to determine when the velocity becomes constant.

Another approach could be to use sensors that can measure the velocity of the ball bearing at different points during its descent and plot a graph to identify when the velocity levels off. Additionally, using a variety of ball bearing sizes and conducting multiple trials can help improve the accuracy of the results.

It is also important to consider other factors such as air resistance and the shape of the ball bearing, as they can affect the accuracy of the results. Overall, it would be beneficial to have a detailed procedure and data analysis plan in place to ensure reliable and accurate results. I encourage further discussion and refinement of this plan to make it a successful and informative investigation of Stokes' law.