Force, Motion & Velocity

Force is a vector quantity. When several forces act on a body simultaneously, a net equivalent force can be calculated by vector addition.

A net non-zero force is required to change the state of a body. For a body in motion, the velocity will change depending on the direction of the force acting on it.

If a net force acts on a body in motion, its velocity will increase in magnitude, if the direction of the force and velocity are same. If the direction of net force acting on the body is opposite to the direction of motion, the magnitude of velocity will decrease. However, if a net force acts on a body in a direction perpendicular to its velocity, the magnitude of velocity of the body remains constant. Such a force changes only the direction of velocity of the body. Thus, velocity of a body changes as long as a net force is acting on it.