Q45 / 54 · JEE Advanced 2020 (Paper 2) · Physics
A rod of mass and length pivoted at one of its ends, is hanging vertically. A bullet of the same mass moving at speed strikes the rod horizontally at a distance from its pivoted end and gets embedded in it. The combined system now rotates with an angular speed about the pivot. The maximum angular speed is achieved for . Then

A rod of mass and length pivoted at one of its ends, is hanging vertically. A bullet of the same mass moving at speed strikes the rod horizontally at a distance from its pivoted end and gets embedded in it. The combined system now rotates with an angular speed about the pivot. The maximum angular speed is achieved for . Then

- Correct answerA
- B
- Correct answerC
- Correct answerD
Solution
The net torque on the system (rod+bullet) will be zero about hinge point. Therefore, we can apply the principle of angular momentum conservation about hinge point.
From angular momentum conservation,
For maximum angular velocity,
Hence, the correct answer is options: 'A', 'C', 'D'.