How does Logger Pro calculate velocity and acceleration from photogate data?

When photogates are used to study the motion of an object, the velocity and accelerations are calculated with a different algorithm than the algorithm used for motion detector data. The reason for this difference is that motion detector data is recorded with uniform time intervals. When studying accelerated motion with photogates, the time intervals are not uniform.

An excellent article describing this situation can be found in the April, 1997 issue of The Physics Teacher. The article written by William Leonard is entitled "The Dangers of Automated Data Analysis."

The article describes a different way to calculate velocity and acceleration when photogates are used. This calculation is used in Logger Pro software, LabQuest, and our calculator-based software. Logger Pro help includes the detailed calculations on the page "Advanced Photogate Setup."

See also:
TIL 1011: How does Logger Pro calculate velocity and acceleration from Motion Detector data?
TIL 2275: How can I compare my g measurements to a local value and improve their accuracy?