NEWTON'S SECOND LAW OF MOTION
Newton's second law deals with nonuniform motion, or velocity change, and why it occurs:
NEWfON'S SECOND LAW, A body acted upon by a force will accelerate in the direction of the applied force. The greater the force, the greater the acceleration will be.
If a body's state of motion is basically defined b velocity (or, more correctly, its momentum), then acceleration is a measure of the change. Acceleratio proportional to the magnitude of the acting force-as one increases, the other does too-and inversely proportional to the body's mass-as one increases, the other decreases.
If a moving body is subjected momentarily to an external force, it will momentarily accelerate in the direction given it by the applied force. Its velocity increases to a new value but not necessarily in the same direction as the force. But if the force is applied continously, then a continuous change of velocity, or tion, takes place. For example, as a planet orbits the sun, there is a continuous change of speed and direction, or a continuous acceleration. The change must be due to some continously applied external force. In this case we know that force is the gravitational attraction of the sun.
