From TeachEngineering - Students learn about Newton's second law of motion: force = mass x acceleration. In other words, a heavy object requires a greater force to move than a lighter object. In a tug-of-war experimental setup using paperclips, rubber bands and text books, they collect data and make calculations, seeing that the force required to move a book is proportional to the weight of the book. They relate their conclusions to how engineers use their understanding of this relationship to d