A vector. This is because the quantity given has a magnitude (20mph) and a direction (North). It is also an example of a velocity.
This measure is an example of velocity, which includes both a speed and a direction.
A velocity vector includes both speed and direction.
First part of the question is 400 miles per hour
Speed or velocity.
About 55 miles per hour.
20 miles per hour north is an example of
30 miles per hour north
If no direction is mentioned, then you have a speed. Example: "30 miles per hour". If the direction is mentioned, then you have a velocity. Example: "30 miles per hour north".
We're not completely sure what you mean by "per hour per second". Going just by what we see in the question, it's an acceleration, not a velocity. "Six miles per hour north" would be a velocity.
This measure is an example of velocity, which includes both a speed and a direction.
North at 45 miles per hour. A vector has a direction and a magnitude.
A velocity vector includes both speed and direction.
Velocity is speed and its direction. "30 miles per hour" is a speed. "30 miles per hour north" is a velocity". "30 miles per hour north" and "30 miles per hour south" are identical speeds but different velocities.
(55 miles per hour) is a scalar. (55 miles per hour heading north) is a vector.
Velocity.
Speed.
10 miles per hour 100 feet per second $25 per hour etc...