Perhaps I am being daft, but to me the Physics package seems, quite surprisingly, to have trouble multiplying by a nonzero, non-square matrix. The test code

restart:

with(Physics):

Matrix(2,2,fill = 0) . Vector(2),

Matrix(2,2,fill = 1) . Vector(2),

Matrix(2,3,fill = 0) . Vector(3);

Matrix(2,3,fill = 1) . Vector(3);

produces the following output:

Error, (in Vector[column]) Matrix index out of range

i.e., the last expression cannot be evaluated; while the test code (where no loading of the Physics package is performed)

restart:

#with(Physics):

Matrix(2,2,fill = 0) . Vector(2),

Matrix(2,2,fill = 1) . Vector(2),

Matrix(2,3,fill = 0) . Vector(3),

Matrix(2,3,fill = 1) . Vector(3);

produces the following expected output:

PS: To be sure, I have from http://www.maplesoft.com/products/maple/features/physicsresearch.aspx downloaded the latest version (2014, March 19, 4:0 hours) of the Physics package for Maple 17 (the version I am running).