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Let I(A) and I(B) be moments of inertia ...

Let `I_(A)` and `I_(B)` be moments of inertia of a body about two axes `A` and `B` respectively. The axis `A` passes through the centre of mass of the body but `B` does not. Then

A

`I_AltI_B`

B

`If I_AltI_B` the axes pareparallel

C

`If the axes are parallel I_AltI_B`

D

`If the axes are not parallel I_AgeI_B`

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem regarding the moments of inertia \( I_A \) and \( I_B \) about two different axes \( A \) and \( B \), we can follow these steps: ### Step 1: Understand the Concept of Moment of Inertia The moment of inertia of a body is a measure of how difficult it is to change its rotational motion about a given axis. It depends on the mass distribution of the body relative to the axis of rotation. ### Step 2: Identify the Axes - Axis \( A \) passes through the center of mass (CM) of the body. - Axis \( B \) does not pass through the center of mass. ### Step 3: Apply the Parallel Axis Theorem The Parallel Axis Theorem states that if you know the moment of inertia \( I_{CM} \) about an axis through the center of mass, you can find the moment of inertia about any parallel axis using the formula: \[ I_B = I_{CM} + Md^2 \] where: - \( I_B \) is the moment of inertia about axis \( B \), - \( I_{CM} \) is the moment of inertia about the center of mass (which is \( I_A \)), - \( M \) is the total mass of the body, - \( d \) is the distance between the two axes. ### Step 4: Calculate Moments of Inertia For axis \( A \) (through the center of mass): \[ I_A = I_{CM} \] For axis \( B \) (not through the center of mass): \[ I_B = I_A + Md^2 \] ### Step 5: Compare \( I_A \) and \( I_B \) Since \( d \) is a positive distance (as \( B \) does not pass through the center of mass), we can conclude that: \[ I_B = I_A + Md^2 > I_A \] This implies that: \[ I_A < I_B \] ### Conclusion Thus, we have shown that the moment of inertia about the axis passing through the center of mass \( I_A \) is less than the moment of inertia about the axis \( B \) that does not pass through the center of mass. ### Final Answer \[ I_A < I_B \]
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