Motion In a Plane

1.Scalar Quantity is the physical quantity which has only magnitude but no direction. It is specified completely by a single number, along with the proper unit. e.g. Temperature, mass, length, time, work, etc.
2. Vector Quantity is the physical quantity which has both magnitude and direction and obeys the triangle/ parallelogram laws of vector addition and subtraction.
e.g. Displacement, acceleration, velocity,
momentum, force, etc.
3. Representation of Vector A vector is represented by a bold face type or by
an arrow placed over a letter,
The length of the line gives the magnitude and the arrowhead gives the direction.
4. Types of Vectors Vectors are classified into two types polar and axial vectors.
● Polar Vectors Vectors which have a starting point or a point of application are called polar vectors. e.g. Force, displacement, etc.
● Axial Vectors Vectors which represent the rotational effect and act along the axis of rotation are called axial vectors. e.g. Angular velocity, angular momentum,
torque, etc.

5.Modulus of a Vector The magnitude of a vector is called modulus of vector. For a vector A, it is represented by | | A or A.

6. Unit Vector It is a vector having unit magnitude. A unit vector of A is written as

It is expressed as