Speed refers to how quickly an object changes its position over time. It is measured in meters or miles traveled per second. Uniform motion involves equal distances covered in equal time intervals, following Newton's second law of motion. Forces like pushes and pulls can cause objects at rest to be set in motion or accelerate existing motion by increasing speed. Common terms include hinge, which joins parts to allow opening and closing, speeding up to increase pace, and slowing down or breakthroughs that solve problems.