Dominoes don t lose energy when they fall

Domino effect.

Xinhua News Agency reported on December 31, 2000 and ** TV on January 6, 2001: In the last minutes of the 20th century, a new domino Guinness World Record was born in the Beijing Summer Palace Sports and Health City Complex and Tennis Hall. Sixty-two young students from China, Japan and South Korea toppled more than 3.4 million dominoes, breaking the previous world record of 2.97 million held by the Dutch.

As you can see from the TV screen, the scene of dominoes falling one after another in an instant is spectacular, and the patterns displayed during this time are colorful and amazing, and there is a certain scientific truth in them.

This is the "domino effect". The energy generated by this effect is enormous.

The physics of this effect is: when the domino is vertical, the center of gravity is higher, and when it falls, the center of gravity falls, and in the process of falling, its gravitational potential energy is converted into kinetic energy, and it falls on the second card, and this kinetic energy is transferred to the second card, and the second card transfers the kinetic energy transferred from the first card and the kinetic energy converted from its own gravitational potential energy in the process of falling, and then passes it to the third card. So when each card falls, it has more momentum than the previous card, so their speed is faster than the other, that is, the energy they push down in turn is greater than the other.

A., physicist, University of British ColumbiaWhitehead once made a set of 13 dominoes, the first of which was the smallest. Length, width, thickness, and not as big as a small fingernail.

Each subsequent volume expands by multiplier, and this data is selected according to the ability to knock down a domino of multiple size when a domino falls. The largest 13th card is 61mm long, wide and thick, and the size of the card is close to that of a playing card, which is equivalent to 20 times the thickness of a playing card. Arrange this set of dominoes at the appropriate spacing, and gently push down the first one, which will inevitably spread to the 13th card.

When the 13th domino falls, the energy released is more than 2 billion times greater than when the first card falls. Because the energy of the domino effect grows exponentially. If you knock down the first domino to use micro-coke, the energy released by the 13th domino will reach 51 joules.

It can be seen that the energy generated by the domino effect is indeed jaw-dropping.

But aWildert didn't make the 32nd domino after all, as it would be 415m high, twice as high as the Empire State Building in New York. If someone really made such a set of dominoes, the skyscraper would be toppled with a finger!

Energy loss is a must, mainly the energy loss in the collision, the key is to cause the next domino to fall, each domino is to undergo the conversion of potential energy to kinetic energy, slightly absorbing the residual kinetic energy of the previous card.

The first blow is after the kinetic energy of the hand push acts on the dominoes.

The gravitational potential energy of the domino falling is converted into kinetic energy, and together with the kinetic energy of the previous domino that you originally received from your hand or the previous domino, plus your own gravity, it touches the next domino and forms a moment to make the next domino fall, and the remaining energy of yourself is lost when you fall to the table.

The cycle repeats, but there is a loss of energy on each collision.

In fact, after a long enough time and sequence, the number of dominoes falling per unit time is constant, in fact, the momentum of the domino falling, gravity does not completely convert the energy into the kinetic energy of the next domino to increase, all they do is to make the next domino slightly off the equilibrium position and with a little velocity, and then rely on the gravity of the next domino to fall. If this is not the case, according to the above, the speed has been increasing, then it will soon be because the impulse is too large, and the next domino will be "uprooted", which is not what the domino decorator wants, because this flying domino may affect the dominoes that should not fall behind.

In fact, the energy loss of the collision solves this problem, but this requires specific calculations and is more complicated.

All in all, there is absolutely no energy greater than the other, there must be a limit.

Of course it does, but the brother on the first floor is not comprehensive.

When the first falls and hits the second, the energy is the kinetic energy ek1 of the first one converted into the kinetic energy ek2 of the second one (more important in this step is the momentum transfer, because the energy e2' after the second fall is derived from the sum of the kinetic energy e1 of the first one and its own potential energy after deducting the mechanical energy loss of the system, e2' = ek1 + ep2-δe).

The main reason for the latter to fall should be the transfer of momentum and not energy, why do you say that? Because most of the energy of the second one is its own potential energy.

This situation will not change until it continues to accumulate and the energy accumulated by the previous depleted state is greater than the potential energy of the latter.

Just like the locomotive will retreat a certain distance before the train starts, so that the whole movement is that the locomotive pulls the first carriage when the second carriage does not move, and then relies on the momentum of the locomotive and the first carriage and the second carriage to transfer, of course, the locomotive still has to do the work in the process, but this is much less effort than pulling all the carriages as soon as it comes!

But the source of the discussion is that, in general, it is still in line with the conservation of energy.

Knock down a domino once, you will fall twice, what is the principle of this?

When a domino falls, its height decreases and the gravitational potential energy decreases; Thus, the velocity is obtained, the kinetic energy increases, and it is the reduced gravitational potential energy that is converted into kinetic energy; This part of the energy is transferred to the next domino, and when the next domino falls, it has more energy, and the speed at which the domino is pushed down becomes larger

So the answer is: gravitational potential; Move; Fast

It can be understood this way. The more you go to the back, the greater the force skin bumps. Because the multi-volt dominoes are "connected".

The gap between them is smaller than their height. When the first domino falls, gravity causes him to smash the next one, and the gap is too small for the dominoes to completely touch the ground and consume all the gravitational potential energy, so this potential energy will gradually be stored in the form of kinetic energy on the next fallen domino. The principle of dominoes can be perfectly explained by Newtonian mechanics.

Quantum mechanics is not needed here.

This involves physics.

If you look at the shape of the dominoes, you can see that they are all in.

It is a high-energy stable state, and only a small amount of energy change can cause it to fall.

Set the spacing of the cards to L, the mass to m, the height to H, the width to F(h>>f), and the initial velocity to 0. Then its energy to the next card can have (h 2-l 2)mg where h>l, and the next card needs (f 2 h)*mg, h>>f, then f 2 h can be seen as 0. ”

To put it simply, the force generated when the previous card falls is much greater than the force required for the next card to fall, so the dominoes can go down until the last card without the external force terminating.