PASCO PS-2138 Goniometer - Manual (Page 11)

Model No. PS-2138 Experiment
11 ®
Analysis
1) Look at the graph of Angle vs. Time. According to the graph, what
angle in radians did you trace out on the board?
Arc Angle =
2) When measured in radians, the arc angle (
θ) is the ratio of the arc
length (s) to radius (r). In this case r is the distance from your elbow to
the pen.
θ = s ⁄ r
According to this theoretical relationship, and your measured values of
θ and r, how far did your hand travel?
s = (theoretical)
3) Measure the length of the arc that you drew and record it below. (Tape a
piece of string to the board exactly over the arc. Mark the endpoints of
the arc on the string, then un-tape the string, lay it straight on a table,
and measure the distance between the marks.)
s = (actual)
4) How does the theoretical value of s compare to the actual distance that
your hand traveled?