Determine the work done by the following. Determine the angles between the forces and the displacements. The forces are in Newtons and the displacements are in metres: (a) F= (1, 2, 3) and Ar= (4, 5, 6) (b) F= (1, 2, 3) and Ar= (4, 5, -6) (c) F = (4, 2, 4) and Ar= (2, -8, 2)