What Is Relative Motion?

Relative motion is the branch of physics in which we study the motion of a body with respect to another moving body. To understand relative motion, consider an example. Suppose you are riding a bicycle. You are standing on a street next to the railway track. A train passes in front of you with a speed of 60 km/h. Now you start moving in the opposite direction of train. Now the next train is coming towards you with the same speed as the last train passed you. You are moving with a speed of 10 km/h towards the train.

Now the speed of the train would appear to you as 70 km/h. Similarly if you are moving toward the direction same as the train with the speed of 10 km/h and the train is at a speed of 60 km/h, the speed of train appears to you as 50 km/h. This is the relative motion. Everything in this universe is moving with the relative motion. If the frame of reference is same then the actual speed would appear to you. Most commonly this effect is observed in the driving while overtaking the other cars. The consideration of frame of reference should be kept in mind while observing the relative motion

Motion is the change in the position of a body relative to other body the body which changes its position relative to the other body is present in the state of motion and the body which does not changes its position relative to the other body is called in the state of rest. This change in the position of one body relative to other is called the concept of relative motion. If two bodies are travelling at the same speed in the same direction parallel to each other they are in the state of rest. Like if a passenger is present in a train and a wall clock is hanging on the wall of the train the passenger and wall clock are in the state of rest with respect to each other.

However if the train passes by a station which is not changing its position then for the person standing at the station the passenger inside the train and the wall clock both are in the state of motion, or in the state of relative motion. In the world motion is always a relative phenomenon and consequently all the parameters defining motion like speed, distance are again relative terms.

Relative motion is the motion of a body relative to the other body