Accelerometer drop tests evaluation

[Umair Shariff]

Good morning everyone! I am a Medical Doctor and have a very basic understanding of physics (Studied till high school). I was very much interested in freefall experiments and wanted to do something by myself. I was interested to see if I can demonstrate the lack of gravitational pull during freefall and to test it, I used the accelerometer in my phone and an app to record the data. I have compiled it all in the attached excel file and was very curious about a couple of things that I noticed in the data.

Note that this could very well be due to flaws of the experiment and may very well not reflect in a very closed system.

1. The graph derived from the freefall tests showed a notch in the accelerometer reading after it was dropped. Has there been any such aberrations in experiments done in closed systems??
2. Once the object is in freefall, the accelerometer showed progressive rise in acceleration along the Z axis, before it hits the ground.

I would appreciate if someone could help make sense of the readings I acquired, if they are artifacts or have these findings been observed in closed system experimentation.

Thank you for your time.

 

[A.T.]

Good morning everyone! I am a Medical Doctor and have a very basic understanding of physics (Studied till high school). I was very much interested in freefall experiments and wanted to do something by myself. I was interested to see if I can demonstrate the lack of gravitational pull during freefall and to test it, I used the accelerometer in my phone and an app to record the data. I have compiled it all in the attached excel file and was very curious about a couple of things that I noticed in the data.

Note that this could very well be due to flaws of the experiment and may very well not reflect in a very closed system.

1. The graph derived from the freefall tests showed a notch in the accelerometer reading after it was dropped. Has there been any such aberrations in experiments done in closed systems??
2. Once the object is in freefall, the accelerometer showed progressive rise in acceleration along the Z axis, before it hits the ground.

I would appreciate if someone could help make sense of the readings I acquired, if they are artifacts or have these findings been observed in closed system experimentation.

Thank you for your time.

1. The release might not be clean and instantaneous.

2. Might be air resistance

 

[Umair Shariff]

2. Might be air resistance

The drop was approximately 1.5 meters, would air resistance factor in at such small distances??

 

[A.T.]

The drop was approximately 1.5 meters, would air resistance factor in at such small distances??

See if it fits your results:
https://en.wikipedia.org/wiki/Drag_(physics)

 

[JRMichler]

Your data will make more sense if you plot total acceleration instead of only one component. The total acceleration is the vector sum of the three components of acceleration in your data.