Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!linus!decvax!decwrl!Glacier!oliveb!hplabs!sri-unix!Cramer%CSL60%ti-csl.csnet@CSNET-RELAY.ARPA From: Cramer%CSL60%ti-csl.csnet@CSNET-RELAY.ARPA Newsgroups: net.physics Subject: Monkey Query Message-ID: <705@sri-arpa.ARPA> Date: Sun, 27-Oct-85 08:52:00 EST Article-I.D.: sri-arpa.705 Posted: Sun Oct 27 08:52:00 1985 Date-Received: Fri, 1-Nov-85 00:16:20 EST Lines: 33 From: NichaelIn an effort to: 1] divert attention from the Newman Machine discussion [which has gone on far too long] 2] reintroduce some actual [albeit low-level] physics back into this bboard and 3] to get a satisfactory answer [which I've never found], I'd like to introduce an old chestnut from my undergraduate mechanics course. [See diagram]. o / \ | | | | o/| /n\ ()| |K| \| |g| | - A [massless] Rope passes over a [frictionless, massless] Pulley. On one side is a Weight [n Kg]. On the other side, level with the Weight, is a Monkey, also weighing n Kg. Both the Monkey and the Weight are initially at rest. The Monkey [as you might have guessed by now] starts climbing the Rope. What is the motion of the Weight [or for that matter, that of the Monkey]? What if the Pulley is not frictionless? What if the Rope is not massless? Over the years I've seen at least FOUR different published solutions to this problem [the monkey stays level as the weight rises, the weight stays level as the monkey rises, the monkey and the weight rise at the same rate, and the monkey rises and the weight LOWERS!!!]. Any takers?? No clever signoff, Nichael -------