# Long desk with one end cut, falls from the other one

1. Sep 9, 2016

### korec123

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
Io=1/12ml^2
F=ma.
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. Sep 10, 2016