Essential University Physics: Volume 1 (3rd Edition)

This has to do with Newton's second law, which states that $F = ma$. According to this equation, whatever direction the force is will be the direction of the acceleration. With this being said, that does not mean that the body is moving in that direction. As discovered in previous chapters, acceleration and velocity are not always in the same direction. Therefore, a body will not always have the same direction of motion as the acceleration (and the net force).