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ERIC Number: EJ1057036
Record Type: Journal
Publication Date: 2015-Apr
Pages: 1
Abstractor: As Provided
Reference Count: 5
ISSN: ISSN-0031-921X
Negative Work Done by a Person
Mungan, Carl E.
Physics Teacher, v53 n4 p224 Apr 2015
If I slowly raise a heavy book one meter up in the air, I do positive work. This work corresponds to an energy transfer. I lose chemical food energy that is consumed by my muscles to lift the book upward. Energy is gained by the book-Earth system in the form of gravitational potential energy that is stored in the gravitational field. But what happens if I slowly lower the book back down by one meter to its original location? The book-Earth system loses all the energy it gained and returns to its starting configuration. I have done negative work this time. But my muscles do not regain their original chemical energy! Where did the lost energy go?
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: N/A
Language: English
Sponsor: N/A
Authoring Institution: N/A