On Mar 27, 2:32*pm, John Jones wrote:
Pentcho Valev wrote:

A stone thrown from a speeding train can do far more damage
than one thrown from a train at rest; the speed of the particle is not
independent of the motion of the object emitting it.

Since JJ never adds his own 2 cents worth to someone else's words,
i will do it for him:
Because the speed of a particle is not independent of the motion of
the object viewing it, the amount of damage a stone thrown from a
speeding train can do depends on the motion of the object it hits.

glird