From PHYS1121 (extended) and MATH1231 calculus.
Mechanical resonances.
A forced unbound oscillation where the induced frequency is approaching the natural frequency of the physical system such as a bridge and is represented by a second order non-homogeneous differential equation with a forcing function below.
[maths]my'' + cy' + ky = F_{0}cos(\omega t)[/maths]
Skipping to the chase, the solution to the differential equation is:
[maths]y = Acos(\omega_{0}t) + Bsin(\omega_{0}t) + \frac{F_{0}t}{2m\omega_{0}}sin(\omega_{0}t)[/maths]
...and when physical systems experience this kind of unbound forced oscillation, it is known as resonance and THAT IS WHEN YOU GET THE FUCK OUT OF THERE.
This is represented by collapsing bridges when soldiers all march at the same time or when the wind coincidentally sets up those frequencies.
Also applies when some idiot with a microphone walks too close to another microphone and/or speakers (whatever) and you hear this increasing high pitched sound which fucks your ears over.
Helen Patterson is hot
(she was one of my psyc lecturers)
i found the iraqi CAD lecturer for my ENGG1000 pretty damn hot damn hotter.