Hi Dave,
you are correct on the initial condition thing and I got burnt on it previously by calculating the theoretical motion integrating XdotC as opposed to deltaXdotC.
Anywho, the TRAP* software for the data I've been processing comes out with a THIV of 19.7kph at 126.7ms.
The routine I wrote using vbscript in DIAdem returned 21.53 kph at 126.6ms.
The canned routine from DIAdem returned 21.73 kph at 130ms.
I borrowed your spreadsheet(Thanx) and inserted our data and sampling intervals which returned 21.52 kph at 126.6ms.
We've been debating here at work if the TRAP software uses Simpsons integration or Trapezoidal. But the time of flight is still the same.
*TRAP (Test Risk Assessment Program) August 8, 2002 Copyright (C) 2000 Texas Transportation Institute
