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Question #42434
The Question
A uniform rod of cross-sectional area , Young's modulus , and coefficient of linear expansion is initially at a uniform temperature of . It is placed horizontally on a smooth floor, wedged between two fixed rigid blocks. The faces of the blocks in contact with the rod are smooth inclined planes making an angle of with the horizontal. The ends of the rod are cut to perfectly match the incline. The rod is constrained by a smooth horizontal channel so that it cannot move vertically or bend. The ends of the rod are then maintained at steady temperatures of and , while its lateral surface is thermally insulated. Assuming the blocks do not deform, what is the magnitude of the normal force exerted by each inclined plane on the rod in the steady state?
Options
- A.
- B.
- C.
- D.
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Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Variable_Constraint
Develop pure symbolic logic skills by mastering algebraic constraints without relying on numerical data.
Concepts Behind This Question
Normal Force at Angles|Steady State Temperature Gradient|Young's Modulus Sensitivity
Why This Question Is Tricky
Common Mistakes
This question tests the coupling of thermo-elasticity with static equilibrium under geometric constraints.
A common trap is treating the rod as a simple 1D free body and assuming the normal force equals the internal thermal stress ().
Another trap is incorrectly resolving the normal force vector (e.g., instead of ).
Furthermore, students must correctly apply the steady-state temperature gradient to find the average thermal strain, avoiding the mistake of using the boundary temperatures directly.
Quick Facts About This Question
Question Information
| Subject | Physics |
| Chapter | Laws of Motion - Class 11 Part 1 |
| Concept | Normal Force at Angles |
| Difficulty | 8 |
| Cognitive Load | 7 |
| Target Solve Time | 160 sec |
| Access | Free |