# Relative Velocity

Relative velocity is given by time rate of change of position of one object wrt another. Relative velocity of a body B with respect to some other body A means velocity of B as recorded by an observer sitting on A. Mathematically,

Relative velocity of B wrt A:

Fig. 1

# Graphical method to find relative velocity

When two bodies move at an angle Î¸ with each other, then their relative velocity is given by:

Fig. 2

# Direction

Note: If Î¸ = 90Â°, then  and .