If you sneeze in a weightless environment, as some of the astronauts have done, your body would move backwards and upwards. In order for a motion to happen, a force is needed. So, why does an astronaut's body move when they sneeze? What are the forces that occur during the sneeze? Write (or draw) your thoughts in Notes on your handheld computer.

Picture a propeller or fan blowing air. Think about how the accelerating air from the propeller relates to your description of the forces found during a sneeze in space. What is accelerating the air? Will your almost frictionless cart move when the propeller is turned on? Will it still move when you add more friction? What are the forces that will make the cart move? Write (or draw) your ideas in Notes on your handheld computer.