As a "heavy-hearted" person, when I was a child, I sat in the classroom and always worried about a problem, that is, the ceiling fan above my head suddenly fell and cut off my head.
First of all, we must know that a rotating fan is indeed a dangerous object, whether it is a table fan or a ceiling fan. Generally speaking, the minimum speed of a table fan is about 500 revolutions per minute, which is 8 revolutions per second, while the minimum speed of a ceiling fan is about 200 revolutions per minute, which is 3 to 4 revolutions per second. On the Internet, we can easily find relevant experimental videos, all kinds of vegetables, fruits, and even chicken feet can be easily cut off by ceiling fans.
Therefore, we must be vigilant and do not try to touch the rotating fan under any circumstances.
If the fan is so dangerous, is it possible for the ceiling fan overhead to fall off? Because the installation structure of the ceiling fan is very strong, the top is a steel bar buried in the ceiling, the lower part is connected by a U-shaped hook, and there are screw locks, unless the structure is rusted and the screws are loosened due to disrepair, or the building structure of the roof itself has problems, otherwise it will not fall off.
The most important thing is that a rotating ceiling fan is less likely to fall than a stationary ceiling fan.
Why? For a stationary ceiling fan, it is subjected to a downward gravity and an upward pull, both of equal size and opposite directions. When the ceiling fan rotates, the blades will push the air downward, that is, a downward force is exerted on the air, and the force and the reaction force always appear in pairs, the two are equal in size and opposite in direction, so the ceiling fan at this time is also subjected to an upward reaction force, this reaction force will cancel out part of the gravity, and the pulling force of the ceiling fan will be reduced accordingly, and it will naturally be more difficult to fall.
What if it falls?
Although the risk of falling ceiling fans is small, it is not impossible, and there are examples of ceiling fans falling in real life, but even falling ceiling fans are not as dangerous as we think. First of all, the overall structure of the ceiling fan cannot collapse all at once, plus there are wires connected, so the fall of the ceiling fan is usually a relatively slow process. Secondly, even if the wire of the ceiling fan is broken and falls all at once, it will not become a "blood droplet" that spins rapidly. Because after the wire is torn, due to the lack of continuous power supply, under the action of air resistance, its speed will be drastically attenuated, and it will lose its damage almost instantly.
Of course, if a ceiling fan falls down, it will not shave off its head, which does not mean that there is no danger when the ceiling fan falls.
The biggest danger posed by a falling ceiling fan is "smashing". The roof of an ordinary family home is usually not very high, so the fall of the ceiling fan usually does not cause very serious injury, but it is different in public places, such as schools or shopping malls, the roof of these places is usually relatively high, can reach 3 to 4 meters, calculated at this height, if the weight of the ceiling fan itself is more than 5 kilograms, then its final fall speed can reach seven or eight meters per second, this speed can not only smash people, but also may kill people if they are smashed smartly.
So, when we find that a ceiling fan is at risk of falling, try not to stand underneath it.
So, if a ceiling fan really spun like a "blood droplet" and flew out, can it cut off the head? On this issue, scientists have really done experiments, and the results have found that the rotating ceiling fan hitting the neck of the dummy will indeed cause serious injuries, and even cause fractures, but this force is not enough to shave off the head entirely, and it seems that the head and neck of the person are still relatively strong. However, the fact that the head will not fall off does not mean that it will not die, so when the ceiling fan really falls, the first thing we have to protect is the head and neck.