Problem $4$: For the tetrahedron shown below, a force $F_1=901l$ acts along the edge $DB$ and another force $F_2=-100$hat$(k)$ acts at point $B.$

a$)$ Determine the magnitude of the moment the forces $F_1$ and $F_2$ produce about the $x$ axes,

b$)$ Determine the magnitude of the moment the forces $F_1$ and $F_2$ produce about the axes $CB.$

c$)$ Find the perpendicular distance between point A and force $F_1$ line of action. $(30$ pts $)$