Questions: What is the best definition of speed? Speed is the change of direction of an object when the object is moving. Speed is the law that an object at rest will remain at rest unless a force acts upon it. Speed is the measure of how fast an object is moving. calculated by dividing distance by time.

Solution Steps

We are provided with three different definitions of speed. Our task is to identify the most accurate one.

1. First Definition: "Speed is the change of direction of an object when the object is moving."

   • This definition is incorrect because speed does not involve direction; it is a scalar quantity that only measures how fast an object is moving.

2. Second Definition: "Speed is the law that an object at rest will remain at rest unless a force acts upon it."

   • This definition is incorrect as it describes Newton's First Law of Motion, not speed.

3. Third Definition: "Speed is the measure of how fast an object is moving, calculated by dividing distance by time."

   • This definition is correct. Speed is indeed a measure of how fast an object is moving and is calculated by dividing the distance traveled by the time taken.

Final Answer