SPECIAL SYMBOLS

Apart from the usual ones, I use the following symbols:

W, alacrity, and subscripted variations thereon, is use for quantities with dimension velocity squared.

M, sloth, and its variations, is used for quantities with dimension inverse velocity squared.

W_ij is $(1/\rho)C_{ij}$, an elastic modulus divided by density.

$\theta$ is the angle from the stated axis

C is $\cos (\theta)$

S is $\sin (\theta)$