* Speed is how fast something is moving. It only tells you the magnitude (amount) of the motion.
* Velocity is how fast something is moving *and* in what direction. It tells you both the magnitude and direction.
Velocity equals speed when the motion is in a straight line and in one direction.
Here's why:
* Straight line: If an object moves in a straight line, its direction doesn't change.
* One direction: The direction of motion is consistent.
Examples:
* Car traveling north at 60 mph: Speed = 60 mph, Velocity = 60 mph North
* Ball thrown straight up: Speed changes throughout the flight, but the velocity is always upward (positive) until the ball reaches its peak and then downward (negative).
When velocity doesn't equal speed:
* Circular motion: An object moving in a circle has a constant speed but constantly changing velocity because its direction is always changing.
* Changing direction: A car turning a corner has a changing velocity even if its speed remains constant.
In summary, velocity and speed are only equal when the motion is in a straight line and in one direction.
