I solved it!
It turns out that I had my equation for x wrong. If we let u = 2d tan(θ2) denote the distance between the point where the ray enters the block and the point where it exits, and we take the entry point to be the origin, then the first reflected ray has equation y = x*tan(90-θ1), and...
Homework Statement
A ray of light enters a glass block of refractive index n and thickness d with angle of incidence θ1. Part of the ray refracts at some angle θ2 such that Snell's law is obeyed, and the rest undergoes specular reflection. The refracted ray reflects off the bottom of the block...
If at first you don't succeed...
OK, here goes round two, guided by TSny's advice.
k_{seg}=\frac{ka}{\Delta\!x}
\Delta\!L_i=(f(x_i+\Delta\!x) - (x_i+\Delta\!x)) - (f(x_i) - x_i)=f(x_i+\Delta\!x)-f(x_i)-\Delta\!x=\Delta\!f-\Delta\!x
\Delta\!E_i
=\frac{ka}{2\Delta\!x}(\Delta\!f-\Delta\!x)^2...
A linear elastic strip of natural length a and stiffness k lies between x = 0 and x = a. Each point on the strip is transformed by a differentiable, monotone increasing function f.
a) Characterise the change in potential energy.
b) Given the boundary conditions f(0) = 0 and f(a) = b, choose f...