**ERIC Number:**EJ891960

**Record Type:**Journal

**Publication Date:**2007-Jan

**Pages:**6

**Abstractor:**As Provided

**Reference Count:**7

**ISBN:**N/A

**ISSN:**ISSN-0031-921X

Elliptical Orbit [arrow right] 1/r[superscript 2] Force

Prentis, Jeffrey; Fulton, Bryan; Hesse, Carol; Mazzino, Laura

Physics Teacher, v45 n1 p20-25 Jan 2007

Newton's proof of the connection between elliptical orbits and inverse-square forces ranks among the "top ten" calculations in the history of science. This time-honored calculation is a highlight in an upper-level mechanics course. It would be worthwhile if students in introductory physics could prove the relation "elliptical orbit" [arrow right] 1/r[superscript 2] "force" without having to rely on upper-level mathematics. We introduce a simple procedure--Newton's Recipe--that allows students to readily and accurately deduce the algebraic form of force laws from a geometric analysis of orbit shapes.

Descriptors: Physics, Science Instruction, Motion, Scientific Principles, Computation, Mechanics (Physics), Introductory Courses, Algebra, Geometric Concepts, Teaching Methods

American Association of Physics Teachers. One Physics Ellipse, College Park, MD 20740. Tel: 301-209-3300; Fax: 301-209-0845; e-mail: pubs@aapt.org; Web site: http://scitation.aip.org/tpt

**Publication Type:**Journal Articles; Reports - Descriptive

**Education Level:**N/A

**Audience:**N/A

**Language:**English

**Sponsor:**N/A

**Authoring Institution:**N/A