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Tyrannosaurus rex forelimbs physics as teaching topic (free pdf)

Ben Creisler

A new article:

Scott A. Lee and Joshua D. Thomas (2014)
Forelimbs of Tyrannosaurus Rex: A pathetic vestigial organ or an
integral part of a fearsome predator?
The Physics Teacher 52, 521-254
doi:  http://dx.doi.org/10.1119/1.4902192

In this paper, we examine a first-year torque and angular acceleration
problem to address a possible use of the forelimbs of Tyrannosaurus
rex. A 1/40th-scale model (see Fig. 1) is brought to the classroom to
introduce the students to the quandary: given that the forelimbs of T.
rex were too short to reach its mouth, what function did the forelimbs
serve? This issue crosses several scientific disciplines including
paleontology, ecology, and physics, making it a great starting point
for thinking “outside the box.” Noted paleontologist Kenneth Carpenter
has suggested that the forelimbs of T. rex were an integral part of
its predatory behavior. Given the large teeth of T. rex, it is assumed
that they killed with their teeth. Lipkin and Carpenter1 have
suggested that the forelimbs were used to hold a struggling victim
(which had not been dispatched with the first bite) while the final,
lethal bite was applied. If that is the case, then the forelimbs must
be capable of large angular accelerations α in order to grab the
animal attempting to escape. The concepts of the typical first-year
physics course are sufficient to test this hypothesis by solving .
Naturally, students love solving any problem related to Tyrannosaurus