Physics is intended for a two-semester college course in introductory physics using algebra and trigonometry. Our main goals in writing this book are • to present the basic concepts of physics that students need to know for later courses and future careers, • to emphasize that physics is a tool for understanding the real world, and • to teach transferable problem-solving skills that students can use throughout their lives. We have kept these goals in mind while developing the main themes of the book.