Difference between relative velocity and average …

Differences between average velocity and relative velocity

• Average velocity of a body is sum of all displacements divided by total time elapsed  . Suppose a person starts from point A and after displacements in series and turnings on its paths he finally reaches a point B.
• Then Net displacement = AB and if we divide it with time interval   then we get average velocity as if he was travelling straight to B and relative velocity is actually composition of two velocities and is always defined with respect to an observer who is also moving.
• A person moving on a cycle say with velocity v1 and another walking in the same direction with velocity v2. Now both can observe each other state of motion. But if walking man observes the cyclist he will observe a velocity  v1 - v2 as if he is at rest. The cyclist will observe the man’s velocity as if he himself is at rest = v2 -v1   both are observing relative velocities but the result of measurement is different in magnitude as well as direction.
• So relative velocity is never average. The two are different by definition.
• In daily life the relative velocity sometimes amazes us.
• Suppose a man is walking with umbrella in rain. he saw that rains are falling vertically down when he is at rest.
• Now he starts to increase his speed then it happens that falling rain starts hitting his umbrella at an angle from vertical and he must turn his umbrella forward at an angle to save himself from raindrops.
• So relative to man the rain appears to fall at an angle with the vertical.