speed of a pendulum - Kangaroo

Hi,

I'm trying to do a few things:

1. Make a pendulum which swings back and forth, using Kangaroo. I know the length of the chord, the starting (swing-out) angle, gravity, the mass of the thing on the end of the pendulum.

2. Output the speed of the pendulum at an (as-yet undefined) time interval, until it stops, to a spreadsheet.

I've attached the definition that I've made a start on (nb. I'm not an engineer, so please excuse any inefficiencies in the way I've set this up)..!

Would anyone be able to help me:

a. Make my pendulum simulation more accurate (I don't quite understand how the units for "unary force" are working)...

b. help me output the speed of the pendulum to a spreadsheet (I have gotten as far as getting a length of arc based on start point - I'll be using these numbers to drive something else, later on...)

I'm guessing that if I can somehow output the list of distances along the trajectory of the arc and at set time intervals, then I can make the speed calculations in the spreadsheet, by finding the difference between a length and the one before it and that gives me #/time interval?

Thanks in advance!

EDIT:

One successful method for compiling single-line data stream to multi-line "log" for a spreadsheet is to use "firefly" "data log" then output to spreadsheet using "GHowl"

Still need some help with the pendulum physics though...