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

In summary, the problem involves finding the final velocity of a desk lying on a table, with one end angled at 45 degrees. The desks have different masses and thicknesses, and the moment of inertia of a thin long rod is given. The biggest challenge is incorporating the moment of inertia into the solution. One approach is to use conservation laws to avoid dealing with forces.
  • #1
korec123
8
0
Sorry for my english at the beginning. :) I am not really into academic(physic) english.
1. Homework Statement
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.

Homework Equations


Io=1/12ml^2
F=ma.

The Attempt at a Solution


I don't 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 don't 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,
 
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  • #2
korec123 said:
how to approach this one
With kinetics problems, your first thought should be whether you can avoid having to deal with forces by using conservation laws. What conservation laws apply here? Might these get you to the answer?
 

Related to Long desk with one end cut, falls from the other one

1. How does the length of the desk affect its stability?

The longer the desk, the more likely it is to tip over when one end is cut. This is due to the increased leverage and weight on the non-cut end.

2. Why does the desk fall from the non-cut end?

The non-cut end of the desk is still attached to the floor, creating a pivot point. When the cut end falls, it creates a force that causes the non-cut end to lift and eventually fall.

3. What factors contribute to the desk falling?

The weight of the desk, the length of the desk, the angle at which it is cut, and the type of material the desk is made of all contribute to the desk falling from the non-cut end.

4. Is there a way to prevent the desk from falling?

Yes, the desk can be reinforced with additional supports or bracing to distribute the weight and prevent it from tipping over. Alternatively, a shorter desk or a desk made of a stronger material may also be less likely to fall.

5. Can this phenomenon be observed in other objects besides desks?

Yes, this principle of weight distribution and leverage can be observed in various objects, such as see-saws, bridges, and even tall buildings. It is an important consideration in engineering and design to ensure stability and safety.

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