Setting Up a Pendulum Experiment to Test a Program

In summary: I'm actually planning to use a strobe light to intermittently flash the pendulum. This will cause the pendulum to swing back and forth rapidly, and the fast movement will cause the pendulum to swing in an erratic manner.
  • #1
franznietzsche
1,504
6
A while back i posted a thread on a program designed to analyze and predict the motion of a pendulum. Now i need to set up an experiment to test the program. For those who don't remember/didn't see the last thread, the program can predict the motion of the pendulum at any time in its swing, though its accuracy is unknown, hence the purpose of the experiment.

I need to somehow devise a method for measuring the position of the swinging pendulum, i have easy access to a video camera for frame by frame analysis, as well as a strobe light that i can set to a speicific number of flashes per minute.

The best idea i could come up with was to use a poster board back drop with gradations marking where the pendulum should be at certain time intervals from release (the markings would be based upon the programs predictions) and then compare the pendulums position on the video with the markings. I was thinking due to an issue with perspective (the distance between the pendulum and the markins combined with the wide displacements i planned on testing would cause the same problem as a measuring cup with gradations located on the outside) parallax measurements could be necessary in order to calculate the actual position to then compare with the data.

Any other ideas?
 
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  • #2
Yeah, use the video camera as the swinging mass & parallax won't be a problem. Just kidding.

I'm curious if your program can predict the possibly chaotic motion of the pendulum. The period behaves well over extremes of amplitude but the actual position vs. time can become chaotic. The textbooks typically give only the equations valid when sin(theta) is approx. theta.
 
  • #3
Originally posted by mmwave
Yeah, use the video camera as the swinging mass & parallax won't be a problem. Just kidding.

I'm curious if your program can predict the possibly chaotic motion of the pendulum. The period behaves well over extremes of amplitude but the actual position vs. time can become chaotic. The textbooks typically give only the equations valid when sin(theta) is approx. theta.

the motion only becomes chaotic in the case of both damped and driven pendulums as i recall, which the program does not address, it is written for a simple pendulum only.
 
  • #4
I actually designed and constructed this experiment, using a vertically driven pendulum. Though my methods were laughably crude, and do not warrant mention. (My resources were extremely limited.)

How are you planning to drive the pendulum... are you planning to drive the pendulum?
 

FAQ: Setting Up a Pendulum Experiment to Test a Program

1. How do I set up a pendulum experiment to test a program?

To set up a pendulum experiment, you will need a pendulum, a stand or support to hang it from, a timer or stopwatch, and a computer with the program you want to test. First, attach the pendulum to the stand or support and make sure it can swing freely. Then, open the program on your computer and set up the parameters you want to test. Start the timer or stopwatch and use the pendulum to trigger the program. Record the results and repeat the experiment multiple times to ensure accuracy.

2. How do I calibrate the pendulum for accurate results?

To calibrate the pendulum, you will need a ruler or measuring tape. Measure the length of the pendulum from the point of suspension to the center of mass. Then, use the equation T=2π√(L/g) to calculate the period of the pendulum, where T is the period, L is the length, and g is the acceleration due to gravity (9.8 m/s²). Adjust the length of the pendulum until the calculated period matches the actual period recorded by the timer or stopwatch.

3. What variables should I control in my pendulum experiment?

In a pendulum experiment to test a program, you should control the length of the pendulum, the angle of release, and the initial displacement. These variables will affect the period and amplitude of the pendulum's swing, which will in turn affect the results of the program being tested. By controlling these variables, you can ensure that any changes in the program's output are not due to changes in the pendulum's motion.

4. How can I analyze the data from my pendulum experiment?

To analyze the data from your pendulum experiment, you can plot the results on a graph to visualize any patterns or trends. You can also use statistical methods, such as calculating the mean or standard deviation, to determine the average results and the level of variation. Additionally, you can compare the results from different trials to see if there are any significant differences or if the program's output is consistent.

5. What are some potential sources of error in a pendulum experiment?

Some potential sources of error in a pendulum experiment include air resistance, friction at the point of suspension, and human error in timing or measuring. To minimize these errors, you can conduct the experiment in a vacuum or use a low-friction pivot for the pendulum. It is also important to take multiple trials and calculate the average results to reduce the impact of any outliers or mistakes in the data collection process.

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