Per VABS Manual for Users:
When pounds are used for force and feet for length, the unit of mass must be slug = lb-sec2/ft. If inches are used for length along with pounds for force, then the unit of mass must be lb-sec2/in.
SI units are not mentioned. Is it safe to assume the following:
length |
force | mass | stress |
|---|---|---|---|
in |
lbf | slinch (lbf·s²/in) | psi |
ft |
lbf | slug | lbf/ft² |
mm |
N | tonne | MPa |
m |
N | kg | Pa |