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Question #77082
The Question
A non-uniform rod of length (in ) is placed on a smooth horizontal table. One end of the rod is attached to a vertical wire with torsional constant (in ). The linear mass density of the rod varies as , where is the distance from the attached end and is a positive constant (in ). An angular displacement sensor measures the angle of the rod. The sensor has a constant positive zero error (in ), meaning it reads when the wire is untwisted and exerts no torque. The rod is rotated until the sensor reads (in , with ) and is released from rest. What is the maximum angular speed (in ) of the rod during its subsequent motion?
Options
- A.
- B.
- C.
- D.
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Multi-Concept_Bridge
Master problems that require linking physics and math concepts to solve complex competitive questions.
Concepts Behind This Question
Zero Error Correction|Physical Pendulum Inertia|Torsional Oscillations|Integration
Why This Question Is Tricky
Examiner Levers
Dimensional Analysis
Tests if the student verifies units/dimensions before selecting.
Difficulty Boost : +2Common Mistakes
This question tests the synthesis of experimental error analysis with rigid body dynamics.
Students often mechanically plug in the given initial angle () as the amplitude, failing to recognize that the restoring torque is governed by the true physical equilibrium, requiring the subtraction of the zero error .
Furthermore, the non-uniform mass distribution traps students who incorrectly assume a uniform rod of equivalent mass () or treat the mass as concentrated at the center of mass ().
The correct approach requires integrating the continuous mass distribution from first principles and applying the true physical amplitude to the simple harmonic motion velocity relation .
Quick Facts About This Question
Question Information
| Subject | Physics |
| Chapter | Units and Measurements - Class 11 Part 1 |
| Concept | Zero Error Correction in Instruments |
| Difficulty | 5 |
| Cognitive Load | 6 |
| Target Solve Time | 140 sec |
| Access | Free |