**Motion in a plane- Notes**

**Scalars and vectors**

Rectilinear motion is motion that occurs in a straight line.

Entities that are described completely with the help of a number along with its unit are called scalars

A number along with the unit that represents the measure of a physical quantity is called its magnitude.

Mass, distance, temperature and time are scalars.

Entities that require specification of the line of action or direction in addition to their magnitude to complete their description are called vectors.

Displacement, velocity, acceleration and force are vectors.

**Operations and vectors**

In the graphical method of vector addition, either the triangle Law of addition or Parallelogram Law addition is used.

In vector addition, the tail of the second vector always coincides with the head of the first vector.

Vectors obey the Commutative or Associative Law of Addition.

To subtract two vectors, you must use the concept of addition of vectors after reversing the direction of the second vector.