Thursday, 20 July 2017

kinematics - Why do far away objects appear to move slowly in comparison to nearby objects?


When we are in a moving train, nearby stationary objects appear to go backwards. In Physics, relative velocity can be employed to explain the phenomenon:




velocity of object w.r.t train = velocity of object - velocity of train



Far away stationary objects, however, appear to move slowly in comparison to nearby objects. Here the concept of relative velocity seems to fail. Why is it so? Does it mean that relative velocity formula is also dependent on the distance between the two objects?



Answer



It's because the angle under which a certain distance appears to you depends on how far away the object you are looking at is. I mada a diagram: One object is far away, one object is close. Traveling by the same distance, you see a large angle for the closer object and a small angle for the far object.Thus the angle grows slower for far away objects and thus it seems that you travel more slowly with respect to them.


enter image description here


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