Set up an infinite row of dominos and knock over the first one

In summary, the energy source for a domino cascade is gravitational potential energy (GPE). Each standing domino contains its own GPE, which allows the cascade to continue indefinitely. However, the efficiency of energy transfer decreases over time due to sound, heat, and mechanical vibration, resulting in a constant speed for the cascade. The initial energy in the system was stored when the dominos were first set up.
  • #1
godspeed
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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.
 
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  • #2
The primary energy source for a domino cascade is gravitational potential energy (GPE); every time a domino falls, its GPE is converted into kinetic energy, thus fueling the cascade.
 
  • #3
In a domino cascade, not only will the progression occur, it will actually accelerate! The acceleration effect is cause by the fact that the prior domino, now tilted with force, hits the next domino below the top. This angular action increases the speed of the next dominos top relative to the previous one. And so on.
 
  • #4


Originally posted by godspeed
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?

The energy in the next falling domino doesn't just come from the energy transferred from the domino that hits it. If that were the case, then the cascade would eventually stop. But each standing domino also contains it's own potential energy, which was given to it by it's being lifted into an unstable equilibrium by whoever set them up. This will most probably be enough to keep the cascade going for eternity.

The kinetic energy of the striking domino only has to have enough force to overcome the threshold energy that trips the domino out of it's vertical unstable equilibrium. How much energy comes from that domino falling over is a functioon of the geometry of the domino and the strength of the gravitational field, which you haven't specified.
 
  • #5
are you sure it would get faster and faster? cos with enough time would not the line be falling at the speed of light? (asuming they don't break from each inpact of hitting another one)
 
  • #6
Originally posted by Gara
are you sure it would get faster and faster? cos with enough time would not the line be falling at the speed of light? (asuming they don't break from each inpact of hitting another one)

No, it would not accelerate continuously. The acceleration to which Pallidin referred also increases the impact between one domino and the next. Sound waves and heat as well as mechanical vibration of the individual dominos will increase, thus decreasing the efficiency of energy transfer from each collission. This loss of efficiency will fairly quickly reach a state of equalibrium with the enrgy being fed into the system, resulting in a constant speed.

BTW, in case you're wondering where the energy originally entered the system to make this appearance of perpetual motion, the gravitational potential energy was stored in the system when the dominos were first being set up.
 

1. How is an infinite row of dominos physically possible?

Technically, an infinite row of dominos is not physically possible as it would require an infinite amount of space and dominos. However, a very long row of dominos can be set up to create a visually similar effect.

2. How many dominos would be needed to create an infinite row?

To create a long enough row that appears to be infinite, it would require thousands or even millions of dominos. However, as mentioned before, it is not truly infinite.

3. Can the first domino be knocked over without any external force?

No, the first domino would require some external force to be knocked over. This could be done manually or with the use of a device such as a lever or a ball rolling down a ramp.

4. How does the force of each domino affect the next one in the row?

As each domino falls, it exerts a force on the next one in the row, causing it to also fall. The amount of force required to knock over each domino increases as the row gets longer.

5. What is the scientific explanation behind the domino effect?

The domino effect is based on the principles of energy transfer and conservation. When the first domino falls, it releases potential energy which is converted into kinetic energy, causing it to knock over the next domino and so on. This transfer of energy continues until all the dominos in the row have fallen.

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