Physical quantities fall into two types. A scalar quantity has magnitude (size) only. Mass, distance, speed, time and energy are scalars. If you say a bag has a mass of 2 kg, nothing more is needed.
A vector quantity has both magnitude and a direction. Force, velocity, displacement, acceleration and weight are vectors. A force of 5 N means little until you say which way it acts, such as 5 N to the left, 5 N to the right or 5 N downwards.
A vector can be drawn as an arrow. The length of the arrow shows the magnitude, so a longer arrow means a bigger vector. The direction the arrow points shows the direction of the vector.
