• Question 1 on the 2012 Waves and Compressible Flow past paper concerns waves through an elastic solid. How do we show that the waves are not dispersive?
  • 2014 Question 2(a): "Let \( I(t)=\int_a^b f(k)\mathrm{e}^{\mathrm{i}\psi(k)t}\,\mathrm{d}k \)

    where \( f(k) \) is continuously differentiable, and \( \psi(k) \) is real-valued and twice continuously differentiable. Explain schematically why you would expect the behaviour of \( I(t) \) as \( t\rightarrow\infty \) to be dominated by values of \( k= k_* \) satisfying \( \psi^\prime(k_∗) = 0. \)" — how much detail is needed for 4 marks?

Last modified: Wednesday, 6 May 2026, 4:04 PM