Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: What is wrong with this equation ?

  1. Sep 8, 2010 #1
    A block of mass m1 ϭ 2.00 kg and a block of mass
    m 2 ϭ 6.00 kg are connected by a massless string over a pul-
    ley in the shape of a solid disk having radius R ϭ 0.250 m
    and mass M ϭ 10.0 kg. These blocks are allowed to move
    on a fixed block-wedge of angle ␪ ϭ 30.0° as in Figure
    P10.37. The coefficient of kinetic friction is 0.360 for both
    blocks. Draw free-body diagrams of both blocks and of the
    pulley. Determine (a) the acceleration of the two blocks
    and (b) the tensions in the string on both sides of the
    pulley.

    [PLAIN]http://img820.imageshack.us/img820/9199/36360522.jpg [Broken]

    (m1 + m2)a = m2gSin30 - [tex]\mu[/tex]m1g - [tex]\mu[/tex]m2gcos30

    what is wrong with this equation ?
     
    Last edited by a moderator: May 4, 2017
  2. jcsd
  3. Sep 9, 2010 #2
    You neglect the momentum of inertia of the pulley.
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook