mcgeer@kim.berkeley.edu (10/31/85)
From: mcgeer@kim.berkeley.edu (Rick McGeer) >Date: 30 Oct 85 13:31:01 EST (Wednesday) >From: MJackson.Wbst@Xerox.ARPA >In-Reply-To: <8510300838.AA18569@sri-unix.ARPA> >Cc: MJackson.Wbst@Xerox.ARPA, Physics@SRI-Unix.ARPA > >Simple answers to these questions quickly get confounded in the >ambiguity of "The Monkey. . .starts climbing the Rope." It is simplest >if we take this to mean that the Monkey exerts a force Fm on the Rope >which exceeds MG (where M is n Kg and G is the acceleration of gravity). >Then by considering tension in the Rope it is clear that: > >If the Rope is massless and the Pulley is frictionless and massless then >the Monkey and the Weight both accelerate upward at the same rate A = >Fm/M - G. Not quite correct. Since both the monkey and the rope weigh M, the total mass on the rope is 2M, hence Fm = 2M(G + A) hence A = Fm/2M - G. Picky, picky, picky. -- Rick.