Laser in front of a wall - mathemathical physics

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Homework Help Overview

The problem involves a laser rotating in front of a wall, where the laser's rotation is described mathematically in relation to the speed of light and the distance to the wall. The original poster is exploring the timing of when an observer first sees the laser spot on the wall and how fast that spot moves at a specific angle.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • Participants discuss the timing of the laser's rotation and the implications of the light's travel time. There are attempts to derive expressions for angular velocity and round trip time for light. Questions arise about the measurement of angles and the relationship between the laser's rotation and the observer's perception of the light spot.

Discussion Status

Participants are actively engaging with the problem, raising questions about assumptions and clarifying the relationships between variables. Some guidance has been offered regarding the mathematical treatment of the problem, but there is no explicit consensus on the approach to take.

Contextual Notes

There are discussions about the assumptions related to angle measurements and the implications of approximations in the calculations. The original poster expresses uncertainty about the correctness of their reasoning and the appropriateness of certain mathematical techniques.

  • #31
Your earlier definition of ##t_L## was the round-trip duration at a particular angle. In this case, however, you need the times (not durations) of the arrivals back at the origin from two different (but close) angles.
 
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  • #32
Right! Ah, how could I miss that -.-

So, total time should be ##t_1=t+t_L## if ##t_L## is the round trip duration. Similar for ##t_2##.

Since the difference ##t_2-t_1## is small, I guess it is the same as if I calculate ##dt## from ##t_1## or from ##t_2##.
 

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