What is a Scalar and what is a Vector?

You need to know that

• A scalar is something that has magnitude without direction
  
  
• A vector is something that has magnitude and direction

To put it more simply we will use two examples, power (which is a scalar) and acceleration (which is a vector).

Power has magnitude (an amount of measurement which in this case is Watts) but it does not have any direction, hence it's a scalar!

Acceleration has magnitude (an amount of measurement which in this case is meters per second ms-1) and it also has a direction where it acts, hence it's a vector!



Make sure you know a few examples incase you get asked in the exam.

Do not confuse velocity with speed or mass with weight.

Speed is a scalar and has can have any direction, on the other hand velocity does have direction so it's a vector. Mass is a scalar (measured in kg) but it does not act in any direction, weight which is mass multiplied by the acceleration due to gravity (w=mg) must be a vector since gravity acts in a certain direction.



Typical exam questions will ask something along the lines of

1. What is the difference between a vector and a scalar?
   
2. Describe what a scalar quantity is and give an example.
   
3. Give two examples of vectors and describe why they are vectors.

Remember... the answers are usually all the same so be sure to look at how they are answered in the mark schemes!