Planetary Interiors: General Principles
Moment
of Inertia
- For example, an object
with mass m, circling about you on a wire with length r, has a moment of
inertia given by I=mr2. Note that the less concentrated the
mass, the greater is the moment of inertia.
- For objects with nice,
regular shapes, the moment of inertia is given by I=kmr2, where k
is simply a number.
The moment of inertia for a
spinning body is determined by its response to an external force, or a torque:
- For example, a spinning
top, with a particular mass distribution, wobbles differently depending on how its mass is
distributed....
- For example, the
gravitational interaction between the Sun, Earth and Moon, causes the Earth to wobble, and
that wobble is indicative of how mass is distributed inside the Earth....
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