Question

1) Define speed .
2) what is velocity ?

Answer 1

the rate at which someone or something moves or operates or is able to move or operate.is known as speed
the speed of something in a given direction is called velocity

Answer 2

speed --- the speed of an object is the magnitude of its velocity (the rate of change of its position); it is thus a scalar quantity.[1] The average speed of an object in an interval of time is the distance travelled by the object divided by the duration of the interval;[2] the instantaneous speed is the limit of the average speed as the duration of the time interval approaches zero.
velocity --- The velocity of an object is the rate of change of its position with respect to a frame of reference, and is a function of time. Velocity is equivalent to a specification of its speed and direction of motion.