Question

distinguish between speed and velocity

Answer 1

Speed is a measure of how fast an object is moving so it's the distance traveled per unit time. Velocity on the otherhand is the rate at which an object changes a position. Speed is a scalar quantitiy while velocity is a vector quantity. so to measure velocity you also consider the direction of the movement while measuring speed does not.

Answer 2

speed : distance travelled per time taken to travel that distance
a scalar
velocity: displacement / time
a vector