Motion in a plane

Scalar Quantities:

The quantities which have magnitude but no direction are termed as scalars.

Examples:

Mass, time, length, distance, temperature, energy, work, pressure, specific heat, electric charge, potential, current, frequency, etc.,

Vector Quantities:

The quantities which have both magnitude as well as direction are termed as vectors.

Examples:

Displacement, velocity, acceleration, moment, force, momentum. torque, impulse, amplitude, magnetic induction, electric field intensity, current element, etc.

Some Definations in Vector Algebra:

1. Like vectors or Parallel vectors:

Two vectors (representing same physical quantity) are called like vectors, if they are parallel to each other, however their magnitudes may be different are called Like vectors or Parallel vectors.

2. Equal vectors:

Two or more vectors (representing same physical quantity) are called equal vectors if their magnitudes and directions are same are called Equal vectors

3. Negative vector:

A vector having the same magnitude and opposite direction of a given vector is called Negative vector.

4. Null vector or Zero vector:

A vector whose magnitude is zero and whose direction is in determined is called Null vector or Zero vector.

5. Unit vector:

A vector whose magnitude is equal to one is called Unit vector.

6. Position vector:

The vector used to specify the position of a point with respect to some fixed point (say origin ‘O’) is called Position vector.

If P(x, y, z) is a point in 3D space, then the position vector of P is  

If   is a point 3D space, then the position vector of this point is 

If   then magnitude of  is  

If   and are α , β , γ  the angles made by with X, Y and Z axes respectively,

then       &