kinematics class 11 JEE MAINS

Some Definition Distance: Distance between two points is the length of actual path travelled by the particle. It is a scalar quantity.
Unit : m(metre)
Displacement: Displacement is a vector  drawn from the initial position (A) to the final position (B)
Unit :  m(metre)

Relative Velocity: Relative velocity is used to denote the aircraft moving in the wind or boats moving through the water, etc. The velocity is measured within the object according to the observer. It can be measured using the use of an intermediate reference frame. In simpler terms, this can be the vector sum of the velocities. The relative velocity formula is expressed as

Where V_ABis the velocity with respect to A and B, V_BC is the velocity with respect to B and C and V _AC is the velocity with respect to A and C.Let us consider two objects, A and B moving with velocities V_a and V_b with respect to a common stationary frame of reference, say the ground, a bridge or a fixed platform.
The velocity of the object A relative to the object B can be given as,
V_ab = V_a - V_b
Similarly, the velocity of the object B relative to that of object a is given by,
V_ba = V_b - V_a
From the above two expressions, we can see that
V_ab = -V_ba
Although the magnitude of both the relative velocities is equal to each other. Mathematically,
|V_ab| = |V_ba|