A beam AB has a rectangular cross-section, where point A is the
origin of the
coordinate system, and point B has coordinates (1.2, -0.3, 2.4)
The vector r1 = (1i+12j+1k)m, is perpendicular to the axis AB of
the beam, and is parallel to the thin dimension of the
On the other hand, vector r2=(29.1i-1.2j-14.7k)m, is perpendicular
to both the axis
AB of the beam as well as to r1. The force P applied on point B of
the beam has the coordinate
direction angles (in degrees) as 144, 72 and 60. If the magnitude
of the force is 100 N,
a) Determine the moment of this force about r1.
b) Determine the moment of this force about r2.
The correct numerical answer given by the professor is, mr1= -258.7
N-m and mr2=-75.97 N-m;