Newton's Laws of Motion Mechanical Universe When you drive across a bridge, you expect it to remain stable. You also expect to speed up or slow your car in response to traffic changes. In both cases, you deal with forces. The forces on the bridge are in equilibrium, so it stays in place. In contrast, the force produced by your car engine causes a change in motion. Isaac Newton discovered the laws of motion that describe these situations. Chapter Outline: Forces Newton's First Law Newton's Second Law Mass and Weight Newton's Third Law Common Forces Drawing Free-Body Diagrams The Open Courses Library introduces you to the best Open Source Courses.