Would it be fair to say that what Newton is stating is the modern
equation of Impulse, not Force?
This response is just to further support the answer that was provided by Philip Wood. I was recently confused by Newton's use of "impressed forces", particularly in regards to Corollary 1 of the Laws. But after some digging around, I stumbled across a book written by James C. Maxwell titled "Motion and Matter" in which Maxwell clarifies Newton's meaning:
Article XLIV. - The Second Law of Motion.
Law II. - Change of motion is proportional to the impressed force,
and takes place in the direction in which the force is impressed.
By motion Newton means what in modern scientific language is called
momentum, in which the quantity of matter moved is taken into account
as well as the rate at which it travels.
By impressed force he means what is now called Impulse, in which the time during which the force acts is taken into account as well as
the intensity of the force.
Maxwell, later on, rephrases Newton's 2nd Law:
Article LII. - Statement of the Second Law of Motion in Terms of
Impulse and Momentum.
The change of momentum of a body is numerically equal to the impulse which produces it, and is in the same direction.
Here is the text for reference: http://strangebeautiful.com/other-texts/maxwell-matter-motion.pdf