* Speed is the rate at which an object covers distance. It is a scalar quantity, meaning it only has magnitude (size).

* Velocity is the rate at which an object changes its position. It is a vector quantity, meaning it has both magnitude and direction.

Instantaneous speed is the speed of an object at a specific moment in time. Instantaneous velocity is the velocity of an object at a specific moment in time.

Since speed is the magnitude of velocity, the instantaneous speed at an instant is equal to the magnitude of the instantaneous velocity at that same instant.

Example:

Imagine a car moving in a straight line. At a certain moment, its velocity is 20 m/s east. This means its instantaneous speed is 20 m/s. The direction (east) is part of the velocity, while only the magnitude (20 m/s) is part of the speed.