Vectors and Scalars
What is a Scalar ?
A scalar is something which is used to describe a property, it is something which has magnitude alone.
Examples of scalars are
- Speed - 20Kts, 20m s-1
- Temperature - 20°C
What is a Vector ?
A vector is something which is used to describe a property, it is something which has both magnitude and direction.
Examples of vectors are
- Velocity - 20Kts HDG 030, 20m s-1 NE
- Acceleration - 9.8 m s-2 towards the center of the earth
Some vectors and scalars look similar but it is important to distinguish between them , we can say a helicopter is travelling at a speed of 100Kts which means that it will cover a distance of 100Nm in 1 Hour but without a start point and a direction we do not know where it will end up.
Speed and velocity are easily confused, but as we can see they are not the same thing.
Mathematically
What this means
We need to understand velocity so we can predict where an aircraft will end up if it flies on a given heading for a set time.
We need to understand acceleration so we can predict if an aircraft is capable of attaining flying speed on a short runway at a given weight.
The methods we use as pilots to solve these problems are usually very removed from the theoretical physics but have their roots firmly based in the theory.
Web references