Green
when you know both speed and direction of an objects motion you know the velocity of an object.
The speed varies according to the refractive index of the objects.
Speed only tells how fast something is going, while velocity tells speed and direction.
Different objects can have different speeds; also, the same object can have one speed now, and a different speed later.
Instantaneous Speed.
Subsonic
slow it down, like you
translatory motion
Speed and direction is called velocity.
The speed of an object at one instant of time is its instantaneous speed.
Velocity
Motion