* Velocity is a vector quantity, meaning it has both magnitude (speed) and direction.
* Speed is a scalar quantity, meaning it only has magnitude.
Here's why:
* Change in Speed: If an object's speed increases or decreases, its velocity definitely changes. This is because the magnitude of the velocity vector is changing.
* Change in Direction: Even if the object's speed remains constant, a change in direction still results in a change in velocity. This is because the direction of the velocity vector is changing.
Example:
* A car traveling at a constant speed of 60 mph in a straight line has a constant velocity.
* If the car speeds up to 70 mph, its velocity has changed because the magnitude (speed) has changed.
* If the car turns a corner while maintaining a constant speed of 60 mph, its velocity has still changed because the direction of travel has changed.
In summary:
* A change in speed *always* results in a change in velocity.
* A change in direction *always* results in a change in velocity, even if speed stays the same.
