Question

To describe velocity you need to know

Answer 1

the velocity is the speed that something is going, yous need to know the mass in order to calculate the velocity.

Answer 2

to describe velocity, you should have known the DISPLACEMENT of the body(not distance...as displacement includes direction too..it should only be considered)
And, TIME of travel..that is, time taken to displace the body..
so, velocity is expressed as "m/s"

hope this helps u..
cheers!!