* Speed: This refers to how fast an object is moving. If the speed is increasing or decreasing, the object is definitely in motion.

* Direction: This refers to the path the object is taking. Even if the object maintains a constant speed, if it's changing direction, it's considered to be in motion.

Examples:

* A car driving straight down a road at 60 mph: This car is in motion because it has speed.

* A ball rolling in a circle: This ball is in motion because its direction is constantly changing, even if its speed is constant.

* A plane flying in a straight line at 500 mph: This plane is in motion because it has both speed and a constant direction.

Important Note: An object at rest has zero speed and doesn't change direction.