# $F=ma$ 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? Jan 8, 2021 at 13:39
• The components (x, y) become (-x, -y) I believe
– JD12
Jan 8, 2021 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. Jan 8, 2021 at 13:53
• Thank you very much!
– JD12
Jan 8, 2021 at 13:54

## 1 Answer

Yes, since force is a vector quantity you can have a negative force - simply meaning a force acting in the opposite direction to whatever you have defined as positive.

• Thank you very much
– JD12
Jan 8, 2021 at 13:41