A car travels 300 km south for 4 hours.What is its velocity?

Answer 1

300km/4 hr = 75 kph = velocity = speed

but if it's going south, on an x y coordinate system, you might call that -75 kmp

speed is always positive, but velocity can be either negative or positive depending on the direction

going left on a number line is negative speed, right is positive

on a 2D graph, right is east and positive, left is west and negative,

up is north and positive, down is south and negative