differentiate between speed and velocity
Velocity: Velocity is defined as the displacement of a body produced per unit time.
Velocity=Displacement / Time.
It is a vector quantity as it has both magnitude and direction. For example,The expression' 50km/hr towards North' is velocity as it has both magnitude as well as direction.
Speed:Speed is defined as the distance of a body travelled per unit time.
Speed= Distance / Time
It is a scalar quantity as it has only magnitude . Example, The expression' 50km/hr' is speed as it has only magnitude.
For a moving body, Velocity can be zero but speed cannot be zero. This is because a moving body will cover at least some distance in a time interval but the displacement can be zero if the initial and final position of the body is same.
Example: A truck is moving at a "speed" of 70 km per hour. It describes speed of the truck. A truck is moving at a "velocity" of 70 km per hour towards the North. It describes velocity of the truck.