Why do passengers have to stand behind the security line when the train enters the station?

It was too windy. There are many trains that do not stop when they enter the station, they are very fast, they will form a kind of air pressure, and when the time comes, they will bring people who are close to them, especially those who are skinny, it is very dangerous, so you need to stand behind the safety line.

It's safer to stand behind the waiting line, as there will be some scratching marks when the car comes by. If you get closer, you'll be hurt inadvertently

This is related to the flow of gases and pressure, which can be caused by the movement of air as the train enters the station, which can lead to the danger of pressing passengers towards the train if they do not stand behind the safety line.

Because when the train enters the station, the air flow rate near the train will be accelerated, and the flow rate of the gas is fast and the pressure is small, so the air pressure near the train is small, and the air pressure in the distance is large, and the passengers in the safety line will be pushed to the train by the thrust formed by the strong air pressure difference, which poses a threat to safety.

It is to avoid passengers running on the train without stopping steadily, and they may fall under the tracks, which may also cause their own personal insafety accidents.

When the train is moving, it will drive the air around it, and if people get too close to the train, then there will be accidents, so when waiting for the train, the conductor will ask the passengers to stand outside the safety line. Therefore, when waiting for the train, parents must pay attention to their children. Because the train will cause great harm while moving fast, it is necessary to give children an education from an early age, so that children can remember it.

And this is a physical common sense, chain objects are not only used in car riding events, in fact, there are such performances in many atmospheric knowledge points. Because if the air flow is too large, then it will have an effect. Therefore, for the sake of everyone's life safety, everyone must pay special attention to find something to do for themselves when waiting for the car, and do not rush to get on the bus, after all, the car will not run there all the time.

When I was young, I went to take the train, and at that time I was very curious about why I stood outside the security line. But after learning about this incident, I deeply felt the greatness of science now, and at the same time improving so much knowledge, it also made more people feel how important it is to be safe. And when taking the train, there are always some passengers who have some accidents, that is, things accidentally fall off the back of the train.

At this time, don't pick it up, wait for the train to go before picking it up, this is also for your own safety, so as to reduce the damage caused by the accident.

And everyone must listen to the rules, so that they can solve the problem better. When waiting for the train, you must pay attention to the fact that when the train has not completely stopped, do not get too close, because the car and people can get close to each other for a certain distance, and if you get close, it will also hurt. At this time, the air flow on the inside is slow, but it is enough to squeeze the two states together.

And everyone must pay attention to the fact that taking the train is a very safe thing, but if there is an unsafe incident because of waiting for the train, then the gain outweighs the loss.

Because the pressure of the train is very large, the train is quietly rotten in front of the person who has been reformed, and the wind is particularly strong, which is particularly easy to bring the nuclear passengers to the track, which is very dangerous, so it is necessary to stand outside the safety line.

Because the airflow in the safety line is very fast, the pressure formed by the wide and simple will be earlier than the world, which will cause people to be sucked into the track, so the bird must stand outside the safety line.

Because it is too close to the train, there will be accidents and injuries to others, and the air around the train is very fluid.

When the train is moving, the train drives the air flow around the train, and if the train travels fast, the air flows fast, according to Bernoulli's principle: the pressure is small where the fluid flow rate is fast, and the pressure is strong where the flow rate is small. The gas pressure around the train is small, and if a person is close to the train, it may be pressed onto the train by the atmospheric pressure outside and cause an accident, so people should wait outside the safety line.

The fast-moving object pushes the air to form an air flow, and the rapid movement of the train takes away the air flow, and the train position forms a low air pressure, causing the surrounding air flow to backfill and will roll people under the car.

When the vehicle enters the platform, it will drive the air flow speed between the person and the vehicle to accelerate, and the air flow speed on the outside of the person is slow; According to the relationship between fluid pressure and flow velocity, it can be seen that the air velocity on the outside of the person is slow and strong, while the flow rate on the inside is fast and the pressure is small, which will produce a pressure difference to the inside, pushing the person to the vehicle, which is prone to danger.

Therefore, when waiting for the bus, stand within the safety line to avoid danger.

The same principle is true for airplanes: air of equal mass passes through the upper and lower surfaces of the wing at the same time at the same time, and because the upper surface of the wing is curved and the lower surface is straight, the flow rate of air through the upper surface of the wing is large, and the flow rate through the lower surface is small; Because the air above the wing has a high velocity and less pressure; The air flow under the wings is low and the pressure is strong, so the aircraft receives an upward lift.

This involves the pressure of the fluid in relation to the flow velocity. In a flowing gas, the pressure is low at the location where the flow velocity is large.

When the train enters the station, the air near the train is driven by the train and the flow is generated. The pressure of the air between the passengers waiting for the train and the train decreases due to the flow, and the air pressure behind the passengers is stronger than the pressure of the air between the passengers and the train, and it is easy to press the passengers towards the train and cause accidents, so the passengers should stand outside the safety line when the train enters the station.

Experiment: Holding two sheets of paper in your hand, letting the paper hang parallel to each other, and blowing downward in the middle of the two sheets, you will find that the two sheets of paper are closer to the middle.

When the train is moving at high speed, the surrounding air flow will move with the high speed. According to the principle of fluid mechanics, the density of the air flow at high speed is less than that of the low speed air flow area, and the edge of the low speed air flow zone will generate pressure towards the high-speed air flow area, and if the passenger is too close to the edge of this area, it will be sucked in, which is why it is necessary to stand outside the demarcated safety area.

The faster the velocity of an object, the less pressure it has on its surface. Because the pressure difference will create a pressure difference, pushing people towards a high-speed moving car.

Because according to Bernoulli's principle, the greater the velocity for the fluid, the lower the pressure.

When the train is running fast, it drives the nearby air to flow rapidly, so that the air pressure around the train is very low.

If a person is standing in close proximity, the pressure difference will create a force in the direction of the train, pushing the person towards the train, which is very dangerous. Therefore, passengers must stand outside the security line and wait for the bus.

When the train enters the platform, it will drive the air flow speed between the person and the car to accelerate, and the air flow speed on the outside of the person is slow at this time, according to the relationship between the fluid pressure and the flow velocity, it can be known that the air flow rate on the outside of the person is slow and strong, and the flow rate on the inside is fast and the pressure is small, which will produce a pressure difference to the inward, pushing the person to the train, and it is easy to be dangerous

So the answer is: small.

When the train enters the platform, it will drive the air flow speed between the person and the car to accelerate, and the air flow speed on the outside of the person is slow, which can be known according to the relationship between the fluid code dry pressure and the flow velocity; The slow and strong pressure of the air flow on the outside of the person, while the fast flow rate on the inside of the person and the low pressure will produce a pressure difference to the inner side of the tamohino, which will push the person to the train and be prone to danger

Therefore, let's shout D