Question

define speed. state it's SI unit. it is a scaler or avector?

Answer 1

speed is defined as ratio of distancce covered to the time taken
s.i unit  m/s
scalar

Answer 2

Speed:- The distance travelled by a body per unit time is called speed.
.: Speed = Distance Travelled/Time taken

or V = s / t
where v = speed
s = distance travelled
& t = time taken

The S.I. Unit of speed is metres per second written as m/sec
It is a scalar quantity.