- #1
pinsky
- 96
- 0
Hello there,
i have a problem with calculating the moment of inertia for the object on the picture. There are two cases I'm observing. In the first case, the obect rotates around the axis located in the center of the big circle, and the little circle can't rotate around the axis located in it's center.
Note that the smaller circle is mounted on the big one, it it not carved into it replacing the part of the big circle in that area. That is why Jbig=1/2 MR2 R being the radius of the big circle
In this case, we get the whole J by the parallel axis theorem.
J=JM + Jm
where Jm= 1/2 mr2 + ml2
How does the equation change if we allow the small circle to rotate around the axis located at its center while the axis of rotation for which we calculate J remains the center axis of the big circle?
What is the physical explanation for that?
tnx
[PLAIN]http://img848.imageshack.us/img848/2126/vztrajnostni.gif [Broken]
i have a problem with calculating the moment of inertia for the object on the picture. There are two cases I'm observing. In the first case, the obect rotates around the axis located in the center of the big circle, and the little circle can't rotate around the axis located in it's center.
Note that the smaller circle is mounted on the big one, it it not carved into it replacing the part of the big circle in that area. That is why Jbig=1/2 MR2 R being the radius of the big circle
In this case, we get the whole J by the parallel axis theorem.
J=JM + Jm
where Jm= 1/2 mr2 + ml2
How does the equation change if we allow the small circle to rotate around the axis located at its center while the axis of rotation for which we calculate J remains the center axis of the big circle?
What is the physical explanation for that?
tnx
[PLAIN]http://img848.imageshack.us/img848/2126/vztrajnostni.gif [Broken]
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