Tutorial details

Section I: Biceps contractions

In Questions A-D, students consider how the biceps muscle can cause the forearm to rotate toward the upper arm. Students then model the arm as two rods with a hinge (elbow) connected by a string (the tendon). In Questions E-F, students apply their model to the case of a person doing a biceps curl or similar exercise.

Then students use the rotational equivalent of Newton’s second law to determine how the heaviest weight a chimpanzee can support compares to that of a human.

Section II: Triceps contractions

In this section students use a similar model for thinking about the role of the triceps muscle, then use their model to make calculations.

Section III: Supplement

This section guides students through a model of the head and neck muscles of an American football player. Students do computations concerning the force the neck muscles provide to keep the head from rotating in different scenarios.

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There is a review of the definition of torque at the beginning of the tutorial, but it is best if students have already been introduced to torque and the idea of a moment arm.

Equipment

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• tutorial instructor slides
• tutorial student slides or worksheet

Discussion