Video narration
Why does a ball slow down if motion is supposed to keep going? A ball rolls across the floor, then stops. It can seem as if motion runs out, or the ball needs a steady push to keep moving. The ball doesn't slow because motion fades. Friction from the floor and air resistance push against it, changing its motion. Newton's first law says an object at rest stays at rest, while a moving object keeps the same speed and direction unless a net force-the overall push left after forces combine-acts on it. If pushes balance, motion stays unchanged. Inertia is the tendency to keep that state. So why does the ball stop? The floor's friction pushes against it, and air resistance adds to that net force. Remove that opposing net force, and it keeps rolling straight at the same speed.