Why doesn’t a ray of light which emitted by a distant galaxy, say about a thousand light years away, die down in between? I mean how the light rays from galaxies so far away reach us in this day and age, when emitted so long ago? Why isn’t it dampened and lost altogether? What drives the light ra...

Two particles start moving along the same straight line starting at the same moment from the same point in the same direction. The first moves with constant velocity $u$ and the second with constant acceleration $a$. During the time that elapses before second catches the first, the greatest dista...

Suppose I have a bottle of pills and I throw the bottle in the air vertically. I wonder if the pills inside the box also fly up, or do they remain stable at the bottom of the bottle? I tried this experiment several times and I think the pills remain stable. I took the top of the bottle off and mo...