FORCE AS A VECTOR
 

Force is a vector quantity. It can have any magnitude, from the flick of a finger to a swift leg kick, the explosion of powder in a cannon, or the thrust of a rocket engine. Force always has a defined direction as well. You can fire a pop-gun in any direction you want (and bear the consequences if you make a bad choice). Vectors are commonly symbolized using boldface letters of the alphabet. A force vector, for example, can be denoted by the uppercase boldface letter F.
Sometimes the direction of a force is not important. In such instances, we can speak of the magnitude of a force vector and denote it as an uppercase italicized letter F. The standard international unit of force magnitude is the newton (N), which is the equivalent of a kilogram-meter per second squared (kg
m/s²). Suppose that the brick in your spacecraft has a mass of 1 kg and that you push against it with a force of 1 N for 1 s and then let go. The brick will then be traveling at a speed of 1 m/s. It will have gone from stationary (with respect to its surroundings) to a speed of 1 m/s, which might seem rather slow unless it hits someone.