 Let's imagine that this swing is a car, the rope tied to the back simulates the sudden stoppage of a traffic incident. And the pawpaw? Well that's you. When the swing is moving, the pawpaw is moving along with it. Inertia is the property of something to keep moving unless a force is acted upon it. When we pull the rope, that force stops the swing. But the pawpaw doesn't have a rope tied to it, so it keeps moving. The same thing happens in a car. The inertia will keep you moving even if the car suddenly stops, unless you're wearing a seatbelt. The seatbelt reduces the chances of you colliding with the interior parts of the vehicle. It also stops anyone from being thrown from the vehicle or through the windscreen. It's not complicated, and the outcomes of something so simple as putting on a seatbelt are life-saving.