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Question #42352
The Question
A heavy parent nucleus is modeled as a rigid thin rod of length with a non-uniform linear mass density for . It is initially rotating with a constant angular velocity about an axis perpendicular to the rod passing through its geometric center, which is at rest in the laboratory frame. The nucleus undergoes fission by splitting exactly at its geometric center into two fragments. The binding energy per unit mass of the parent nucleus is and that of both fragments is (). Assume all available energy in the center-of-mass (COM) frame is converted entirely into the relative translational kinetic energy of the fragments. What is the relative speed of the two fragments immediately after fission?
Options
- A.
- B.
- C.
- D.
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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
Center of Mass (COM) Frame|Binding Energy per Nucleon Curve|Integration
Why This Question Is Tricky
Common Mistakes
This question tests the ability to distinguish between the laboratory frame and the center-of-mass (COM) frame in a variable-mass/fission scenario.
A common trap is assuming the initial kinetic energy available for the fragments is simply the rotational energy about the geometric center ().
However, because the mass distribution is non-uniform, the COM is shifted from the geometric center, meaning the COM is translating in the lab frame.
Students must correctly apply the parallel axis theorem to find and use the reduced mass of the asymmetric fragments to find the true relative velocity.
Quick Facts About This Question
Question Information
| Subject | Physics |
| Chapter | System of Particles and Rotational Motion - Class 11 Part 1 |
| Concept | Center of Mass (COM) Frame |
| Difficulty | 8 |
| Cognitive Load | 7 |
| Target Solve Time | 160 sec |
| Access | Free |