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In the above question, the angular veloc...

In the above question, the angular velocity will:

A

increase

B

decrease

C

not change

D

nothing can be said

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem regarding the angular velocity when an object sticks to the rim of a rotating body, we can follow these steps: ### Step-by-Step Solution: 1. **Understand the System**: We have a rotating object with an initial angular velocity \( \omega \) and a moment of inertia \( I = mr^2 \), where \( m \) is the mass of the rotating object and \( r \) is its radius. 2. **Moment of Inertia Before Collision**: The initial moment of inertia of the rotating object is given by: \[ I = mr^2 \] 3. **Moment of Inertia After Collision**: When an additional mass \( m \) sticks to the rim of the rotating object, the new moment of inertia \( I' \) becomes: \[ I' = mr^2 + m \cdot r^2 = (m + m)r^2 = 2mr^2 \] 4. **Conservation of Angular Momentum**: Angular momentum before and after the collision must be conserved. The initial angular momentum \( L_i \) is given by: \[ L_i = I \cdot \omega = mr^2 \cdot \omega \] The final angular momentum \( L_f \) after the mass sticks is: \[ L_f = I' \cdot \omega' = 2mr^2 \cdot \omega' \] 5. **Setting Up the Equation**: According to the conservation of angular momentum: \[ L_i = L_f \] Substituting the expressions for angular momentum: \[ mr^2 \cdot \omega = 2mr^2 \cdot \omega' \] 6. **Solving for Final Angular Velocity**: We can simplify the equation by dividing both sides by \( mr^2 \) (assuming \( m \neq 0 \) and \( r \neq 0 \)): \[ \omega = 2\omega' \] Rearranging gives us: \[ \omega' = \frac{\omega}{2} \] 7. **Conclusion**: The angular velocity after the mass sticks to the rim will be half of the initial angular velocity: \[ \omega' = \frac{\omega}{2} \] ### Final Answer: The angular velocity will decrease to half of its initial value.
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