Date: Mon, 1 Nov 2010 16:36:17 -

Author: --- "Paul Lulai"

Subject: Re: LoggerPro and two motion detectors


I believe the process is:
Experiment, set up sensors, select the interface, then select one of the motion detectors, you can reverse the +/- direction from a drop down menu.

Paul Lulai
Physics Teacher
St Anthony Village S.H.
3303 33rd Ave NE
St Anthony Village, MN 55418


-----Original Message-----
From: [] On Behalf Of Krishna Chowdary
Sent: Monday, November 01, 2010 4:17 PM
To: tap-l
Subject: [tap-l] LoggerPro and two motion detectors

Dear colleagues

I want to update a lab where students look at 1-d collisions between
carts on a low friction track using motion detectors to determine
speed of carts before and after interactions. I know that you can hook
up two motion detectors to a LabPro or LabQuest; students do this with
one motion detector at each end of the track. Each detector measures
only the cart closest to it (this requires some care in aiming but
isn't too difficult). However, because the motion detectors are aimed
at each other, the position vs. time graph for each cart have a
negative sign with respect to each other. Last time I did this, I had
students keep track of positive and negative on their own, but this
was a little confusing.

Is there a way in LoggerPro to set the motion detector so that one
motion detector will use "away" from the detector as negative and
"towards" that detector as positive? I know I can have students make
their own calculated column, and will do this if that's the best
option. I hope my question is clear enough.

Thank in advance, as always.