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Re: Kinematics - a vs. t graphs



"You cannot reliably infer the acceleration from samples
of the x and t coordinates, not without some nontrivial
regularization assumptions."

We are using old Vernier software and motion detectors for Workshop
Physics labs in which we generate d, v, and a vs. t graphs. The a vs t
graphs are always noisy, and generally look like the edge of a
carpenter's saw. I'm not familiar with the latest software and
equipment, and wonder if cleaner graphs are now possible.

Despite the difficulties mentioned in the thread above, I expect that
the main issue here is coming from the propagation of error. If the
motion detector takes say 30 readings per second, then I assume that it
calculates 30 average velocities per second, and uses Ludwik's method to
find 30 average accelerations per second. I find that the noise varies
from one machine to another in my room despite similar setups and
conditions.

Gary Hemminger
The Dwight-Englewood School
Engelwood, NJ
hemmig@d-e.org