Date: Thu, 13 Oct 2011 08:59:09
Author: Steve Wonnell
Subject: Re: another Vernier question
On Wed, 12 Oct 2011, Sam Sampere wrote:
> Ok, I've noticed this in the past, but now it's really bugging me because I'm teaching the class.
> If you've ever done N3 using 2 force probes, you'll notice that the
> curves are a tiny bit displaced from one another. I've attributed this
> to the timing differences, collect FP1, then FP2, then FP1, etc.
It must be something like that. It is annoying.
> Now I'm doing an impulse-momentum demo - crash a car into a piece of rubber. Plot the F-t curve and the v-t curve.
> I've set LP to collect 1000 pts/s. I know, the MD cannot do that, so LP sets that to 20 pts/s.
> I start to see the change in v maybe 10 or 15 points BEFORE there is anything on the FP. Why???
> Barring that, it's a beautiful experiment. Integrate F-t, measure delta v, and you get quite good agreement. I'm using LP3.8.4 if that's of any issue with a Vernier MD and a wireless FP.
Interesting. I have the MDs that plug into the LabPro, so for our
apparatus I don't recommend using them because it slows down the Force
probe data collection. But F versus t does give a nice result:
> Sam Sampere
> Syracuse University
> Department of Physics
> 201 Physics Building
> Syracuse, NY 13244
> 315-443-9103 (fax)