Read the following material and then answer the question
The wing shape of the aircraft is flat above and below, and when the wing is parallel to the direction of the air current, the air current is split between the upper and lower parts of the wing (figure 1). The air current above the wing is faster than the air current below the wing. According to the fluid flow, the pressure of the high-speed area is small and the pressure of the low-speed area is strong. It is known that the pressure below the wing is stronger than the pressure above the wing, thus creating an upward lift on the wing. The lift is vertical. When the lifting is greater than gravity, the aircraft rises. The size of the lift is also influenced by the size of the wing, the speed of flight, and the angles of the wing and the surface. In general, the larger the wings, the faster they fly, the more the wings and horizontal angles are right up
In the back of the racing car, there is usually a wing-like device -- the air flow deflector (figure 2) -- the upper surface of the air flow deflector is flat and the lower surface is arc. It's a reverse wing. It's mainly for the high speed of the car. The wheel can hold the ground better
(1) please draw a line under the sentence in the text on the physical principles that generate lift during flight
(2) if the forward edge of the wing is slightly upward and a small angle is in the direction of the air current (e. G. Figure 3), the pressure differential above and below the wing is greater than when the wing is parallel to the direction of the air current, at which point the lift will be (select to be “larger”, “smaller” or “no change”)
(3) installation of air flow deflectors at the back of the racing car, which will enable the wheel to hold the ground better, mainly because of the increase in the number of vehicles to the ground
(4) there is a security line on the train platform, as shown in figure 4, and when the train enters the station, it is dangerous for people to cross the line. Please indicate the reasons for the danger:
(5) what other occasions in life fall within this category according to the characteristic of fluid pressure, as is the case:
