Newton's famous law of motion: "An object in motion tends to stay in motion,
unless acted upon by an outside force [non-verbatim]."

In other words? If the outside force causes a change of motion/velocity
in an object [say a change of one millimeter/second], that change in velocity
will remain until ANOTHER force [along the same vectors, in whole or in part] acts on the object to "change" it's velocity once again.

Velocity = speed X direction

That second change in velocity could either augment, neutralize, or reverse
that first change in velocity. I think I've taken that into account.

For example? An object falling straight down encounters a hypothetical tiny horizontal push.

Ignoring air resistance, assume that the tiny push creates a horizontal velocity vector of two feet per-second. If it takes the object 30 seconds to hit the ground after
the horizontal push, it will miss the target by 60 feet.
The vertical velocity will not affect the horizontal velocity; and the horizontal velocity will not affect the vertical velocity; different vectors of velocity are involved.
I hope I've explained myself.
I think I'm getting rusty with my physics.

Jacob