We'll find the car's speed first, and then use that to find the velocity.
Speed = (distance covered) / (time to cover the distance)
Speed = (240 miles) / (3 hours)
Speed = (240/3) · (miles/hours)
Speed = 80 mile/hour
Now to convert the units, we'll use
-- 1 mile = 1,609 meters
-- 1 hour = 3,600 seconds
(80 miles/1 hour) · (1,609 meter/1 mile) · (1 hour/3,600 second) =
(80 · 1,609 · 1) / (1 · 1 · 3,600) (mile · meter · hour / hour · mile · second) =
35.76 meter/second
Now, to make a velocity, all we need to do is to add the direction to the speed.
So the car's velocity is 80 mi/hr south, or 35.76 meter/sec south .
