If velocity is positive, which would most likely yield a negative acceleration?
Afinal velocity that is faster than an initial velocity.
A time that is less than a half hour.
An initial velocity that is faster than a final velocity.
A time that is greater than a half hour.

Ch4 and ph3 are both covalent since they are composed both of non-metals.    ch4 is non- polar because of  london forces and has a geometry of tetrahedral  ph3 , on the other hand, is umbrella shaped polar and has dipole-dipole intermolecular force (imf) . since ph3 is polar, it has a stronger imf