1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
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: Long desk with one end cut, falls from the other one

  1. Sep 9, 2016 #1
    1. The problem statement, all variables and given/known data
    Picture of problem : http://screenshot.sh/ouZAbUeL9Qzmj We have got a desk,mass m1, length L1 and thickness d, and L1>>d. One of it's ends is angled by 45 degree. At the beginning it is put on the other desk which thickness is also d and mass is m2. I have to find final velocity of the second desk, this one which is lying on the table. We skip friction. I also have information at the end of the task that Moment of inertia of thin long rod, length l, and mass m is 1/12ml^2.
    2. Relevant equations
    3. The attempt at a solution
    I dont really have any idea how to approach this task. What i could is just simply mark all the forces, just what i do every time when i do this kind of question (i mean, i have some mass and i have to find accelerate, whole basically based on 2nd newton law's), but it didnt help. I ve only found that sin of the angle between first desk and the table is sin=d/L1-d. The biggest problem i think is that i dont know how to use info about moment of inertia in this question. If you can explain to me, how to approach this one and how to use moment of inertia i would be grateful. Thanks in advance,

    PS. I am posting on advanced becouse nobody answered me on introductory.
  2. jcsd
  3. Sep 10, 2016 #2


    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted