Re: Newton's Second Law Lab

[Glenn Knapp <kahuna@VCN.COM>]

At 09:12 AM 07/03/2000 -0400, you wrote:
> I am trying to come up with a good lab for high school students to do
> that will clarify and test N2.  I have air tracks available but have the
> following experiences.

I have not done this lab with an air track (only have two).  I do a lab
using Pasco's collision carts which are very low friction and so might
behave somewhat like an air track glider.

I have the students rig up a low friction pulley, a string, the cart, and a
hanging mass to cause the acceleration.  We use a very small mass to cause
the acceleration -- 2 or 3 washers.  This causes the whole system to
accelerate very slowly so that they can get a fairly accurate time for a
given distance of travel.  The weight of the washers is around 0.20
N.  They figure out the acceleration of the whole system from the time and
distance, then use the second law to find the force.  Results are usually
within 10 % or so of the weight of the washers.  I'd be happy to send you a
copy of the lab as an attachment if you are interested.  I don't see why it
wouldn't work with an air track.  Maybe I'll give it a try.

Glenn
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