First Lab

 

1)      Measurement of acceleration due to gravity from a motion detector.

In this experiment my group and I measured the velocity of a ball which is in a free fall.

We use LabPRO on the computer and a motion detector. We placed the motion detector approximately 1.5 meters above the ground and held the ball about 10 centimeters away from the detector. We started recording the data and then released the ball. After the recordings we analyzed the data.

We ended up with two graphs: one is position-time, and the other is velocity-time. We applied the curve fit on the graphs, quadratic and linear respectively.

We differentiated the velocity-time graph’s equation once to get the acceleration (-9.556 m/s^2).

We differentiated the position-time graph’s equation twice to get the acceleration (-9.63 m/s^2).

I gathered values from 5 other groups to calculate the standard deviation.

Hiroshi Matsune: -9.15 m/s^2

Dalton Giovinetti: -9.58 m/s^2

Matthew Cortez: -9.41 m/s^2

Elle Tanjuakio: -9.62 m/s^2

Steven Lee: -9.60 m/s^2

   Measurement of acceleration due to gravity from Video Analysis.

I have measured a ball which is in a free fall to get velocity, position and time values to calculate the acceleration.

I recorded a video of myself, releasing a ball. I uploaded the video to the video analysis software, adjusted the scale and adjusted the origin to be on the top of the ball. And then I clicked on top of the ball repeatedly, once in every two frames, to get the velocity-time and position-time graphs.

I have applied curve fitting two both of the graphs to get equations and then took the derivatives of the graphs to get acceleration.

Then I’ve calculated the standard deviation using values from 5 other people.

Zitong Cheng: -9.6m/s^2

Dalton Giovinetti: -9.83m/s^2

Oscar Chavez: -9.81m/s^2

Jose Zvala: -9.46m/s^2

Sam Trieu: -9.41m/s^2

Write-up on measurement variability.

Uncertainty for the motion detector: Distance is not exactly 1.5 meters and 10 centimeters. Position of the detector.

Uncertainty for the video analysis: Perspective. Camera’s capabilities. Scaling might not be accurate.

Data from motion detector: -9.48 +/-0.138

Data from video analysis: -9.65 +/-0.163

Using the addition method uncertainty: -19.13 +/- 0.301

Since 0.301>0.17 my measurements agree with the uncertainty.

I think the data from motion detector is more useful because we the uncertainty from the motion detector which is 0.138 is smaller than the uncertainty from the video analysis which is 0.163.