Rotational Motion Question 43
Question: ABC is a right angled triangular plate of uniform thickness. The sides are such that $ AB>BC $ . $ I _1,I _2,I _3 $ are moments of inertia about AB, BC and AC respectively. Then which of the following relations is correct?
[AIPMT 2000]
Options:
A) $ I _1=I _2=I _3 $
B) $ I _2>I _1>I _3 $
C) $ I _3<I _2<I _1 $
D) $ I _3>I _1>I _2 $
Show Answer
Answer:
Correct Answer: B
Solution:
- The moment of inertia of a body about an axis depends not only on the mass of the body, but also on the distribution of mass about the axis.
For a given body mass is same, so it will depend only on the distribution of mass about the axis. The mass is farthest from axis BC, so $ I _2 $ is maximum.
Mass is nearest to axis AC, so $ I _3 $ is minimum. Hence, the correct sequence will be $ I _2>I _1>I _3 $ Note: In a rotational motion, moment of inertia is also known as rotational inertia.
