It's correct as written. See sense 9 at http://dictionary.reference.com/browse/shear -- shearing stress is the stress between two blocks pressed together along a plane and moving in opposite directions parallel to that plane.
It's a very nice analogy: the startup is moving fast in one direction and the VC or whatever is moving slowly in another one.
It's much harder to explain impedance concisely. I, for one, never took a circuits class, and I wouldn't expect other CS programs to require one either.
