Relativistic Stick: Can the Hole Contract Enough?

  • Thread starter Thread starter boardbox
  • Start date Start date
  • Tags Tags
    Relativistic
Click For Summary
SUMMARY

The discussion centers on the relativistic effects of a stick of proper length L moving at speed v through a hole of diameter L in a sheet. In the lab frame, the stick undergoes length contraction, allowing it to pass through the hole. However, in the stick's frame, the hole contracts, leading to a contradiction regarding the stick's ability to pass through. The key takeaway is that simultaneity is frame-dependent, complicating the scenario and suggesting that the stick may not fit through the hole as initially assumed.

PREREQUISITES
  • Understanding of special relativity principles, particularly length contraction
  • Familiarity with the concept of simultaneity in different reference frames
  • Basic knowledge of Lorentz transformations
  • Ability to apply relativistic equations to physical scenarios
NEXT STEPS
  • Study the implications of length contraction in special relativity
  • Explore Lorentz transformations and their applications in different reference frames
  • Investigate the concept of simultaneity and its effects in relativistic contexts
  • Examine real-world applications of relativistic physics in high-speed scenarios
USEFUL FOR

Students and enthusiasts of physics, particularly those studying special relativity, as well as educators seeking to illustrate the complexities of relativistic effects in practical examples.

boardbox
Messages
16
Reaction score
0

Homework Statement


A stick of proper length L moves at a speed v in the direction of its length. It passes over a thin sheet with a hole of diameter L cut into it. As the stick passes over the sheet is raised and the stick moves through the hole so that it is underneath the sheet.

Is this a reasonable scenario? In the lab frame the stick is contracted and should easily make it through. However the hole is contracted in the stick frame.


Homework Equations





The Attempt at a Solution


I know that events that are simultaneous in one frame are not in others. So I expect part of the sheet to rise before the rest in the stick frame. Because of that I also expect the stick to be able to pass through (despite being "longer" than the hole) but I'm having difficulty showing it quantitatively. In the stick frame the front of the hole moving and the back of the hole moving should be separated in time by Lv/c^2.

Now if I take that time, and multiply by v, get Lv^2 / c^2 as the distance that the hole would traverse in the stick frame which is less than L and would mean to me that the proposed scenario is impossible. What bothers me with this is it goes against my intuition. Can anyone see where I'm going wrong?
 
Physics news on Phys.org
boardbox said:
… I know that events that are simultaneous in one frame are not in others. So I expect part of the sheet to rise before the rest in the stick frame. …

Hi boardbox! :smile:

If the sheet is at an angle, surely only the width of the stick matters?
 

Similar threads

  • · Replies 26 ·
Replies
26
Views
1K
  • · Replies 44 ·
2
Replies
44
Views
2K
Replies
11
Views
3K
  • · Replies 12 ·
Replies
12
Views
2K
  • · Replies 11 ·
Replies
11
Views
2K
  • · Replies 7 ·
Replies
7
Views
5K
  • · Replies 1 ·
Replies
1
Views
4K
Replies
6
Views
5K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 13 ·
Replies
13
Views
3K