If you look at the dashboard of a moving car, the dial tells you how fast you are going—for example, 60 km/h. In everyday language, we call this 'speed'. However, in the strict world of Physics, there is a massive and extremely important difference between Speed and Velocity based entirely on the concept of Direction.
Speed: A scalar quantity (Magnitude only).
Velocity: A vector quantity (Magnitude + Direction).
Speed Formula: Total Distance / Total Time.
Velocity Formula: Total Displacement / Total Time.
SI Unit: Both are measured in meters per second (m/s).
Speed is the rate at which an object covers distance. It answers a very simple question: "How fast is the object moving?" Speed is a Scalar Quantity. This means it only has a magnitude (a number). It absolutely does not care about what direction the object is traveling in.
Velocity is the rate of change of displacement. It answers two questions simultaneously: "How fast is it moving, AND in what exact direction?" Velocity is a Vector Quantity. It requires both a magnitude (speed) AND a specific direction to be mathematically correct in physics.
Speed is just how fast an object is moving (a scalar). Velocity is how fast an object is moving AND the specific direction it is traveling in (a vector).
Yes! If an object moves from a starting point and eventually returns to the exact same starting point, its total displacement is zero, making its average velocity exactly zero.
Yes, both have the exact same SI unit, which is meters per second (m/s).
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