Question

If we want to know the velocity that an object is traveling , we must know the ?

Answer 1

You're going to want to know the displacement of the object and the time it took to get there. Velocity is displacement/time, so unless you want to do some fancy other math that requires other knowledge (which of course you don't, lol) just the displacement and time will do.

Answer 2

speed = total distance/total time

Answer 3

v = dx/dt