This article is about Video Physics, an older app for iOS/iPadOS only that is no longer being updated. The older app is separate from our newer Vernier Video Analysis Progressive Web App that runs in the browser.

A recent update to Graphical Analysis uncovered a bug in the Video Physics App related to calculated columns. The exported .ambl file from Video Physics has incorrectly formed calculated columns, resulting in bad velocity columns as they are read and parsed in Graphical Analysis. Our older software (Graphical GW) did not attempt to parse the column(s) which hid the bug. Unfortunately, the imported velocity columns cannot be edited into a correct form in Graphical Analysis as the column equations are locked.

The bug in Video Physics will not be corrected as that application is no longer under active development.


A workaround in Graphical Analysis is to create your own velocity column(s) using new calculated columns that you define. To do this, follow these steps:

  1. Click or tap on the three dots at the top of a position column.
  2. Select Add Calculated Column.
  3. Enter a name that is different from X Velocity and Y Velocity but which is descriptive, and enter units.
  4. Click or tap Insert Expression, then choose 1st Derivative.
  5. Check that the Column Y field includes your position column and the Column X field is set to Time. Correct these if necessary.
  6. Click or tap Apply.

Another workaround is to use Vernier Video Analysis. Vernier Video Analysis includes the analysis options that Video Physics does not, so that export is not needed. The analysis options in Vernier Video Analysis are based on those of Graphical Analysis Pro.