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Re: Smart PASCO Pulley



Tim,

The max data rate for the smart pulley is 25 Hz. There are 8 spoke per
revolution, so the max angular speed is (25/8) rev/sec. Much faster than
this, and your data is garbage. Your sign change sounds like a 'strobe'
effect.

I don't understand why you think your spin direction has an associated
sign. The smart pulley does not have a direction encoder. This device
only measures the times from light blocked to light unblocked. Knowing
these times and their associated distances allows one to calculate the
average speed during this time interval.

Good luck,
Sam


On Fri, 28 Mar 1997, Tim Burgess wrote:

I was using the Smart PASCO Pulley today with Science Workshop Software.
The smart pulley is in constant contact with a rotating disk so that
as the disk spins the smart pulley spins.

The angular acceleration should be negative at all times during a
"spin down" of the disk (the angular velocity constantly decreases on
the table and graph of data). Instead there is an alternating pattern
of negative and positive angular accelerations on both the table and
the graph of the acceleration.

Is anyone familar with this equipment and results?

Writing this note makes me wonder if there is a data sampling rate that
needs tweaking...but the question is posed for assistance! Thanks.

Tim Burgess