ERIC Number: EJ1248233
Record Type: Journal
Publication Date: 2020-Mar
Pages: 3
Abstractor: As Provided
ISBN: N/A
ISSN: ISSN-0031-921X
EISSN: N/A
Dynamics of a Spool-Block Atwood System
El Idrissi, Abdallah; Calabrese, Dominic; Hickox, Tyler
Physics Teacher, v58 n3 p173-175 Mar 2020
For many years, Atwood's machine has been used to demonstrate, illustrate, or verify Newton's laws in introductory physics courses. It consists of two objects of different mass that are fastened to the ends of a string that hangs over a pulley. In an idealized situation, one assumes that pulley friction, the string's mass, and changes in the string's length are negligible. Cases in which the pulley's mass is non-negligible may be considered. Advanced students can investigate non-ideal cases in which the string's mass or friction is not negligible or cases in which the masses swing. Computer-based data acquisition tools allow quick and accurate measurements of the acceleration of the objects in the Atwood machine. They enable an instructor to ask probing questions regarding this apparatus while quickly verifying its prevailing physical principles through simple measurements. Two interesting questions that one can ask are: Question (1): "What is the acceleration of the objects in an Atwood machine when both objects are of equal mass with one being an unraveling spool?" Question (2): "Is it possible to determine a mass ratio in which the acceleration of the spool is non-zero while the acceleration of the other object is zero?" The purpose of this article is to discuss these questions and present a way to readily demonstrate the theory governing the motion of this system. The rich physical content of this system allows one to explore fundamental topics such as Newton's laws, energy conservation, and the relationship between torque and angular momentum at a deeper level.
Descriptors: Science Instruction, Physics, Teaching Methods, Equipment, Scientific Concepts, Mechanics (Physics), Motion, Science Experiments, Educational Technology, Technology Uses in Education
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://aapt.scitation.org/journal/pte
Publication Type: Journal Articles; Reports - Descriptive
Education Level: N/A
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: N/A
Grant or Contract Numbers: N/A