Module Introduction

Module 3—Effects of Force on Velocity

Module Introduction

A young girl wearing a red parka and snow boots is playing on the ice in this photograph. She is smiling and laying on her stomach.

Isaac Newton is one of the major figures in the history of dynamics. You’ll see his name throughout this module. In fact, most of the work you’ll complete revolves around Newton’s laws of motion.

Newton’s first law: law of inertia: A body continues in its state of rest or of motion in a straight line with a constant speed unless an external, unbalanced force acts on it.
Newton’s second law: : The rate of change of velocity of an object is proportional to and in the same direction as the unbalanced force acting on it.
Newton's Third Law: : For every action force, there exists a reaction force that is equal in magnitude but opposite in direction.

As you work in this module, keep the following questions in your mind:

How is the motion of an object affected by forces applied to it?
How do unbalanced forces affect the motion of an object?
How do Newton’s laws help explain why motion occurs?
How do you find a reaction force?
How does friction affect moving objects?
How does friction affect making an object move?
How do free-body diagrams, vector analysis, and Newton’s second law help solve moving-object problems?