Chronology Current Month Current Thread Current Date
[Year List] [Month List (current year)] [Date Index] [Thread Index] [Thread Prev] [Thread Next] [Date Prev] [Date Next]

a suggestion

What John M says is correct; the velocity and acceleration data are of
distinctly lower quality than the position data. Any analysis that you
really care about should be done with the position data. e.g., in a free
fall experiment, don't fit a line to the velocity data; fit a parabola
to the distance data. Unfortunately for the air resistance problem, you
have to do much more complicated analysis to make use of the distance
data.

Let me try something simple. I will do real averaging. What can be gained
by sacrificing the number of data points to reduce fluctuations?

The table for the falling ball is shown below. The first four columns are
the same as before (Mac Motion generated data). Column 5 shows spread
sheet calculated accelerations (without any smearing) based on the data
in the first two columns. Column 6 shows three accelerations obtained by
simple averaging of 3, 4 and 3 data points from column 5. Column 7 data


*******************************************************************
t(s) d(m) v(m/s) a(m/s^2) R(N)

1.425 0.655 2.013 9.65
1.450 0.708 2.254 9.65
1.475 0.768 2.494 9.64 0.09
1.500 0.835 2.734 9.60 0.11
1.525 0.904 2.975 9.61 0.10
1.550 0.983 3.215 9.59 0.12
1.575 1.066 3.454 9.54 0.14
1.600 1.155 3.691 9.48 0.18
1.625 1.251 3.927 9.44 0.20
1.650 1.352 4.162 9.38 0.23
1.675 1.458 4.395 9.33 0.26
1.700 1.573 4.632 9.31 0.27
1.725 1.692 4.865 9.33
1.750 1.816 5.035 7.83
*******************************************************************