To Move an Object - Push or Pull?

When an object is pushed at an angle $\theta$ to the horizontal (force directed into the surface as well as along it), the applied force resolves into $F\sin\theta$ (parallel to the surface) and $F\cos\theta$ (perpendicular, pressed into the surface). Since there's no vertical acceleration, the normal force must balance both the weight and this extra downward push:

When the same object is instead pulled at angle $\theta$ (force directed up and away from the surface as well as along it), the vertical component $F\cos\theta$ now acts upward, partly supporting the weight:

$N_{pull}=mg-F\cos\theta.$ …