Goniometer
Suggested Activities
6
!
Angular acceleration is the change between consecutive velocity
calculations divided by the time between samples.
The Goniometer is very sensitive to small variations in the angular
velocity, so you may see a lot of variation in angular acceleration. To make
the angular acceleration data easier for students to interpret, use the smooth
function (in DataStudio) or reduce/smooth averaging (Xplorer GLX). See
DataStudio online help or the GLX users’ manual for details.
Optional Calibration
The Goniometer does not normally require calibration. To increase the
accuracy of measurements made over a limited range of motion, the
Goniometer may be manually calibrated. In DataStudio, click the Calibrate
button in the Experiment Setup window. Set the probe at a known angle,
enter the angle under Point 1 and click the Set button. Set the probe at
another known angle, enter the angle under Point 2 and click the Set
button.
Suggested Activities
Analysis of Gait and other motions
Collect angle data of the knee while walking. Does it approximate simple
harmonic motion? Explain what you observe.
Collect angle data of the hips during walking, fast walking and running.
•
How does the angle of forward rotation compare to the angle of
backward rotation?
•
Compare the left and right hips. Are they symmetrical?
•
Compare the range of movement and period of oscillation for walking,
fast walking and running? What patterns do you observe?
•
Compare data from different students walking at the same speed (walk
side-by-side or use a motion sensor to monitor speed).
•
For that class, make histograms of range of motion and period of
oscillation. Do any patterns emerge?
•
Make graphs of range of motion and period vs. height. Is there a
correlation?
Measure the period of the leg swinging freely and compare it to the period
of oscillation when the subject is walking at his or her most comfortable
pace. For the class, investigate the relationship between leg length,
L
, and
walking period,
T
. For all pendulums
; is this true for human legs
*
?
Analyze non-periodic movements such as throwing, kicking, and lifting.
When performing the movements, move only the joint that is being
measured. You can collect data on the linear motion of lifted, kicked and
T
L
∝
*For a detailed
analysis of the leg
as a physical
pendulum see: A.
Dumont and C.
Waltham, 1997,
Walking,
The
Physics Teacher,
35 (6): 372–376.
