How does a sailboat travel upwind? Students use wind power to study Newton's law of action–reaction and learn that forces are vectors—with both magnitude and direction. By changing the angle of the sail and the direction of the wind, students will soon learn why sailboats need to use an unusual zigzag pattern to cross a lake. A high-quality dynamics cart that relates Newton's laws of motion to real-world applications. Instructions provided. An external fan source is required, but not included.