PASCO ME-6807A Human Arm Model - Manual (Page 21)

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21
Experiment 7: Triceps Extension
Part A
Introduction
Hold a mass in your hand. Stretch your arm straight up. Bend your
elbow at 90° so that your forearm is horizontal and your hand is
close to the back of your head. While keeping your upper arm ver-
tical, lift the mass by extending your elbow.
Predictions
1. As you lift the mass, does your triceps force increase or
decrease?
2. Sketch your prediction of the triceps force versus elbow angle
graph.
Set-up
1. Install the 100 g mass on the
model’s hand.
2. Clamp the arm model vertically and upside-down as illustrated.
3. Lock the shoulder at 0° (straight up).
4. Attach a cord and force sensor as illustrated. You will hold the force sen-
sor in your hand and pull to make the model’s elbow extend.
5. Connect the arm model to the angle sensor. Connect the angle sensor
and force sensor to your interface.
6. Set the sampling rate of the force sensor to 20 Hz.
7. Prepare a graph to plot triceps force versus elbow
angle.
Required Parts of Human Arm Model
Arm
Cord (1 piece)
100 g mass
Other Required Equipment
Angle Sensor PS-2139
Force Sensor PS-2104 or PS-2189
C-clamp SE-7286 (6-pack)