Sunday, October 9, 2011

Treatment of ‘Pseudoforces’ in Introductory Physics Courses

Some blog followers might be interested in a post “Treatment of ‘Pseudoforces’ in Introductory Physics Courses” [Hake (2011)].

The abstract reads:

PhysLrnR’s Hugh Haskell correctly addressed the common misconception raised by Jennifer McElrath that the centripetal force is “a force in and of itself.” As of today, Hugh's post had initiated a 35-post PhysLrnR thread with the illiterate subject heading “Re: Centrifuagal (sic!) force (Was: Computer simulations: how & when are they effective? Research articles?)” on the PhysLrnR archives at . That thread consisting primarily of diverse opinions on the “Treatment of ‘Pseudoforces’ in Introductory Physics Courses.”

For a Socratic Dialogue Inducing (SDI) Lab [Hake (1987, 1992)] that deals with, among other things, the motion of an object moving in a vertical circle (McElrath’s concern), see SDI Lab #3 “Circular Motion and Frictional Forces,” online as a 278 kB pdf at The contentious and perplexing words “centripetal” and “centrifugal” appear nowhere in SDI Lab #3.

For an SDI Lab treatment of the notorious “pinning force” experienced by kids sitting in an accelerating truck or by passengers seated in an airplane accelerating for takeoff, see “Towards Paradigm Peace in Physics Education Research” [Hake (2000)] at On pp. 10-11 is a transcript of a Socratic exchange “Pinning a Kid To Her Seat” based on Section XI “Motion of a kid in a truck- revisited” of SDI Lab #2, online as a 233 kB pdf at

BTW - thanks to Alfredo Louro for reminding us of the classic 1960 PSSC film Frames of Reference, and to Ben Dreyfus (2011) for calling attention to the centrifugal force cartoon at 007 agent Bond, being crushed against the inside of a rapidly rotating Ferris wheel, nevertheless insists that there’s no such thing as “centrifugal force”!

To access the complete 11 kB post please click on

Richard Hake, Emeritus Professor of Physics, Indiana University
Honorary Member, Curmudgeon Lodge of Deventer, The Netherlands
President, PEdants for Definitive Academic References
which Recognize the Invention of the Internet (PEDARRII)

REFERENCES [All URL's shortened by and accessed on 09 Oct 2011.]
Hake, R.R. 2011. “Treatment of ‘Pseudoforces’ in Introductory Physics Courses” online on the OPEN! AERA-L archives at abstract and link to the complete post are being transmitted to various discussion lists.

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