# Unable to understand relative motion

If you sit in a fast moving car on a highway, you will see the objects outside the window moving backwards with respect to you. Assume that your motion is uniform. One would think that all static objects would move backwards with uniform speed.

However, in real, if you sit in the backseat of a van, you will find the background move at a very fast speed from your window. However, if you look through the window of the people sitting in front, the landscape doesn't move as fast. If you carefully follow one part of the landscape (say a stationary patch of grass, or a moving car), you will see it accelerating as it reaches your window.

Why is this so?

P.S. I don't know much physics, so please explain simply.

• Are you asking why when you look look at an object while moving toward it, the object - relative to you - appears to be moving faster toward you when it is closer than when it is further away? As in: if I'm driving down the highway and I'm approaching a stationary traffic cone in the road, it appears to be moving "toward me" much faster than the stationary mountain 10 miles ahead? – Kyle Arean-Raines Jun 25 '15 at 15:55
• If so, as @Ross Millikan says, it's a consequence of geometry and how our brain perceives distances. For example, when I'm 10 feet from the traffic cone, it appears to be much larger than when I'm 100 feet from it. However the mountain, which goes from being 52800 feet to 52710 feet away, does not appear to change much in size. Because one way humans gauge a change in distance is by a change in apparent size, the mountain doesn't seem to Be moving toward me nearly as fast as the cone, even though physics tells us they are moving at the same speed relative to me. – Kyle Arean-Raines Jun 25 '15 at 16:02