| Title | Author | Created | Published | Tags | | ------------------------------ | ---------------------------- | ---------------- | ---------------- | ---------------------- | | Speed, Velocity & Acceleration | <ul><li>Jon Marien</li></ul> | January 28, 2025 | January 28, 2025 | [[#classes\|#classes]] | **Speed, velocity, and acceleration** are all related concepts in physics that describe the motion of an object, but they each have distinct meanings. ## Speed - **Speed** is a scalar quantity that describes how fast an object is moving. It is the rate at which an object changes its location and is calculated as distance divided by time. - **Average speed** is the total distance traveled divided by the total time taken. - **Instantaneous speed** is the speed of an object at a specific moment in time. A speedometer indicates instantaneous speed. ## Velocity - **Velocity** is a vector quantity that describes both the speed of an object and its direction of motion. - Velocity is the rate of change of position and has both magnitude (speed) and direction. - A change in velocity can be a change in the object’s speed or direction of motion. - Because velocity is a vector, it takes into account the path of travel, whereas speed does not. ## Acceleration - **Acceleration** is the rate at which an object's velocity changes over time. - Acceleration is a vector quantity, having both magnitude and direction. - Acceleration can involve a change in the object's speed, direction, or both. - If the change in speed is an increase, the acceleration is in the same direction as the velocity, and if the change in speed is a decrease, the acceleration is in the opposite direction of the velocity. - **Average acceleration** is the change in velocity divided by the time required to produce that change. - **Centripetal acceleration** is the rate of change in velocity associated with a change in the direction of an object's motion. It is always perpendicular to the velocity and points towards the center of the curve. In summary, speed describes how fast an object is moving, velocity describes how fast and in what direction an object is moving, and acceleration describes how the velocity of an object is changing.