速度 (sùdù) refers to the rate at which an object moves or changes position. It is a fundamental concept in physics, often measured in units such as meters per second (m/s) or kilometers per hour (km/h). Understanding 速度 helps in various fields, including transportation, sports, and engineering, as it allows for the analysis of motion and the efficiency of movement. In everyday life, 速度 can be observed in various scenarios, such as a car driving on a highway or a runner sprinting on a track. Factors like friction, wind resistance, and gravity can affect an object's 速度. By studying these influences, scientists and engineers can improve designs and enhance performance in activities ranging from automobile racing to aerodynamics.