i'm new to this forum and from first glance it seems like a great place to learn. i have a pretty simple question regarding dominos. if one was to set up an infinite row of dominos and knock over the first one, will the dominos fall for eternity, or will the energy decrease over time from loss due to sound and heat until one domino simply was not hit with enough force to knock the next domino over? some of my friends think energy will be lost and because of the conservation of energy that they will at some point stop, and others think that once you knock over one domino gravity will always accelerate the next enough to knock the next domino over so that it will fall indefinitely. what will really happen and why? thanks.