# $F=ma$ if $a < 0$

The equation $$F= m\cdot a$$ is known, but what if $$a < 0$$? Is the force exerted negative?

• Force and acceleration are vector quantities, they have magnitude and direction, what does it mean to take the negative of a vector? – Charlie Jan 8 at 13:39
• The components (x, y) become (-x, -y) I believe – JD12 Jan 8 at 13:42
• That's right. Since the answer has already been given I'll just tell you where I was going, if you take the negative of a vector you end up with a vector pointing in the opposite direction. If the original vector pointed in the direction of your force, or in the direction in which your object is accelerating, the negative of that vector just corresponds to a force in the opposite direction, or an object accelerating in the opposite direction. – Charlie Jan 8 at 13:53
• Thank you very much! – JD12 Jan 8 at 13:54