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?
 A: 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.

A: Well thats because in any kind of general physics problem we consider a point object. While you travelling by train,  you see nearer object to move faster than a far away object (say a tower) . What you should be actually seeing a a very tiny point on the nearer object and a very tiny point on the far away object. One more reason (which is a bit biological one) is that when you see a nearer object, you eyeballs tend to follow its position but it doesnt gets much time to follow that object as you are moving fast. However when  you see a far away object, since its far from you, therefore it makes a very tiny angle with your eyeballs. Even though that tiny angle might mean a relative displacement of 10km (depending upon the distance of the object) .
A: One way to explain it is using v=rω from circular motion.  (I am assuming that both the objects move with equal velocity in your question.)
Let's say 2 objects 1 and 2 are at a distance of r1 and r2 respectively, such that r2>r1 and are moving with velocity v in the direction perpendicular to which you are looking at, then you will be looking at their angular velocity (ω1 and ω2 respectively) now ω=vel./radius. Here r1 and r2 act as respective radii for obj. 1 and 2. Now ω1>ω2 because ω is inversely proportional to radius and obj.1 has a smaller radius than obj.2. As a result the object which is farther away from you appears slower.
