Rotational Motion Question 46
Question: A circular disc is to be made using iron and aluminium. To keep its moment of inertia maximum about a geometrical axis, it should be so prepared that:
[AIPMT 2002]
Options:
A) aluminium at interior and iron surrounds it
B) iron at interior and aluminium surrounds it
C) aluminium and iron layers in alternate order
D) sheet of iron is used at both external surfaces and aluminium sheet as inner material
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Answer:
Correct Answer: D
Solution:
- Moment of inertia depends on distribution of mass about axis of rotation.
Density of iron is more than that of aluminium, therefore for moment of inertia to be maximum, the iron should be far away from the axis.
Thus, aluminium should be at interior and iron surrounds it.
