Name _____________________________ Team # _______
Date: _______
Lab 6: Your task in the laboratory activity is to find the net Torque for two different configurations of
the biomechanical arm and compare your value to what is expected. One configuration is with a 50 g
mass in the “hand.” The other configuration is one of your choosing.
For each configuration include the following in your report:





An extended free body diagram with magnitude and direction
of all forces labeled.
A table as in the example.
Calculations for the net Torque
Calculations for the magnitude and angle of the Normal force at
the pivot (elbow joint)
A comment on the result and its difference from the expected
net torque.
Name _____________________________ Team # _______
Date: _______
Part 1: Forearm is parallel to the floor and a 50 g mass is in the hand.

Draw an extended free body diagram with magnitude and direction of all forces labeled.

Fill in a table for the situation. Include all proper table headings.
Force
Caused
BY
ON
X
Y
Torque ()
Write equations for a static
equilibrium condition.

Show example calculations for Fx, Fy, and Torque.

Calculate the net Torque based on your laboratory values. Compare it to the expected
equilibrium condition of net torque = 0.

Calculate the magnitude and angle of the Normal force at the pivot (elbow joint)
Name _____________________________ Team # _______
Date: _______
Part 2: Forearm _____________________ and a ____________ mass is in the hand.

Draw an extended free body diagram with magnitude and direction of all forces labeled.

Fill in a table for the situation. Include all proper table headings.
Force
Caused
BY
ON
X
Y
Torque ()
Write equations for a static
equilibrium condition.

Show example calculations for Fx, Fy, and Torque.

Calculate the net Torque based on your laboratory values. Compare it to the expected
equilibrium condition of net torque = 0.

Calculate the magnitude and angle of the Normal force at the pivot (elbow joint)
Name _____________________________ Team # _______
Date: _______
Application question: A physical therapist is rehabilitating a patient’s arm by having him flex and extend
the arm. She uses a weighted belt that can be attached anywhere on the arm.
a. Where should the therapist put the belt at the beginning of therapy to provide the gentlest
effect? Explain
b. How should the belt be moved as the patient gets stronger? Explain.