Summary For horizontal forces, an object will remain at rest, or in motion at constant velocity, if the vectorial sum of the forces acting on it is zero.
(an object; will remain; at rest, or in motion at constant velocity) (the forces; acting; on it) (the vectorial sum of the forces; is; zero)
an object the forces the vectorial sum of the forces
will remain acting is
at rest, or in motion at constant velocity
on it
zero