Projectile Motion Experiment: Results Too High?

[burakyildiz]

Hello everyone,
I have a homework about projectile motion experiment and I threw small ball over the table and ball did projectile motion at the end of the table and ı recording this motion on motion tracker and motion tracker gave me acceleration of y component of ball as 14.02 m/s^2. But it has to be 9.8 m/s^2 or at least 10 or 9 m/s^2. Why tracker gave me this results? Should i do the experiment again?

 

[A.T.]

Make sure your length calibration is accurate: Use a larger reference object, that is placed right where the trajectory is.

As a control: Use the vertical fall distance position y(t) and the equation: a = 2 * y(t) / t²

 

[Orodruin]

What @A.T. said. You have chosen an object far off to the side of the image as reference. Ideally your reference should be in the middle of the image and quite large.

Furthermore, your axes look quite tilted in comparison to the objects. You want to position the camera at a right angle to the wall and pointing as straight at your experimental setup as possible to avoid artefacts arising from perspective.