The discussion revolves around calculating the rotation rate of a reflected beam of light from a rotating plane mirror. The subject area includes concepts of angular motion and reflection in optics.
Some participants have offered insights into the relationship between the angles and the rotation rates, while others are seeking clarification on the mathematical representation of these relationships. The discussion reflects a mix of interpretations and attempts to understand the underlying principles without reaching a definitive conclusion.
There are mentions of specific angles and the behavior of the reflected beam during the mirror's rotation, indicating potential constraints in the problem setup. Additionally, there is a note about an incorrect equation that may affect the understanding of the problem.
Firstly, describe the reflected anglehidemi said:Homework Statement:: A plane mirror is in a vertical plane and is rotating about a vertical axis at 100 rpm. A horizontal beam of light is incident on the mirror. The reflected beam will rotate at:
The answer is 200 rpm.
Relevant Equations:: 2θ = 2 dθ/dt
If we know the change of angle is twice the incident angle, then the rate of rotation is 2*100 rpm = 200 rpm. Is there a better explanation of it?
I got it. Thanks!collinsmark said:Firstly, describe the reflected anglewith respect toas a function of the angle of the plane.
Secondly, take the derivative.
[Edit: also, your "2θ = 2 dθ/dt" equation is incorrect.]