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ERIC Number: EJ859343
Record Type: Journal
Publication Date: 2009-May
Pages: 2
Abstractor: As Provided
Reference Count: 2
ISSN: ISSN-0031-921X
A More General "U = mgh"
Keeports, David
Physics Teacher, v47 n5 p286-287 May 2009
In problems dealing with the Earth's gravity, students are frequently bewildered by the fact that the two common expressions for potential energy, "mgh" and "-Gm[subscript e]m/r", differ in sign and differ considerably in form. Some textbooks demonstrate that the more familiar first expression is a special case of the more general second equation providing that an object is near to the Earth's surface. In this paper I derive an equation that resembles the familiar "U = mgh" but that applies to an object of mass "m" at any height "h" above the Earth's surface.
American Association of Physics Teachers. One Physics Ellipse, College Park, MD 20740. Tel: 301-209-3300; Fax: 301-209-0845; e-mail:; Web site:
Publication Type: Journal Articles; Reports - Descriptive
Education Level: N/A
Audience: Teachers
Language: English
Sponsor: N/A
Authoring Institution: N/A