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Two spherical shells have their mass uniformly distrubuted over the spherical surface. One of the shells has a diameter of 2 meters and a ma
Question
Two spherical shells have their mass uniformly distrubuted over the spherical surface. One of the shells has a diameter of 2 meters and a mass of 1 kilogram. The other shell has a diameter of 1 meter. What must the mass m of the 1-meter shell be for both shells to have the same moment of inertia about their centers of mass? m = nothing kg
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Physics
3 years
2021-08-06T18:05:35+00:00
2021-08-06T18:05:35+00:00 1 Answers
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Answers ( )
Answer:
the mass m of the 1-meter shell = 4kg
Explanation:
The moment of inertia of a spherical shell is given as;
I = mr²
From the question, we want the two sphere’s to have the same moment of inetia: Thus,
I1 = I2
Where I1 is the moment of inertia of the first spherical shell while I2 is the moment of Inertia of the second spherical shell.
Thus;
m1•r1² = m2•r2²
Where;
m1 is mass of the first spherical shell which is 1kg
r1 is radius of first shell which is = 2/2 = 1
m2 is mass of the second spherical shell which is unknown.
r2 is radius of second shell which is = 1/2 = 0.5
Now,we are are asked to find the mass of the 1m diameter shell and in this case it’s m2.
Thus, let’s make m2 the subject of the formula;
m2 = m1 (r1/r2)²
Plugging in the relevant values ;
m2 = 1(1/0.5)² = 4kg
For both to have same moment of inertia, mass of 1m shell must be 4kg