What planes can t fly, and why can t people?

Your question is actually asking about the flight principle of the airplane, and I will tell you the flight principle of the airplane, and you will be able to answer your question!

Newton's three laws of motion.

First Law: The velocity (v) of an object remains constant unless it is subjected to an external force.

There is no force, that is, the resultant force of all external forces is zero, when the plane keeps flying in a straight line at the same speed in the sky, the resultant force of the aircraft is zero, and the average person imagines that it is different from the imagination that when the plane lands to maintain the same sinking rate and declines, the resultant force of lift and gravity is still zero, and the lift force is not reduced, otherwise the plane will fall faster and faster.

Second Law: The momentum of an object with mass m (p

MV) is proportional to the applied force.

f and occurs in the direction of the force.

This is famous.

f=ma formula, when the object is subjected to an external force, that is, an acceleration is generated in the direction of the external force, when the aircraft takes off and taxi, the engine thrust is greater than the drag, so the forward acceleration is generated, the speed is getting faster and the drag is getting bigger and bigger, sooner or later the engine thrust will be equal to the drag, so the acceleration is zero, the speed is no longer increasing, of course, the plane is already flying in the sky at this time.

The third law: The action force and the reaction force are equal in value and opposite in direction.

If you kick the door, your foot will hurt because the door also exerts the same amount of force on you.

Balance of forces. The force acting on the aircraft should be just balanced, if it is not balanced, the net force is not zero, according to Newton's second law will produce acceleration, in order to analyze the convenience of the force is divided into the balance of the three axes of x, y and z and the balance of the bending moment around the x, y and z axes.

The axial force imbalance will produce acceleration in the direction of the resultant force, and the force on the aircraft in flight can be divided into lift, gravity, drag, thrust, lift is provided by the wing, thrust is provided by the engine, gravity is generated by gravity, and drag is generated by air, we can decompose the force into two directions of force, called. x and.

Of course, there is also a Z direction in the Y direction, but it is not very important to the aircraft, unless it is in a turn, when the aircraft flies in a straight line at equal velocity, the drag in the X direction is opposite to the same thrust size, so the resultant force in the X direction is zero, the speed of the aircraft is unchanged, the lift in the Y direction is the same as the gravity and the opposite direction, so the resultant force in the Y direction is also zero, and the aircraft does not take off, so it will keep flying in a straight line at the same velocity.

In the case of aircraft, the x-axis moment unbalanced aircraft will roll, the y-axis unbalanced aircraft will yaw, and the Z-axis unbalanced aircraft will pitch.

Then there's Bernoulli's law.

Airplanes on flying chess will not fly.

There is no evidence that humans cannot fly. Because the human brain has a flying brain. That means that at some point on Earth, humans may be able to fly.

For various reasons, the loss and degradation of physiological structures leads to the next round of special evolution. In fact, humans are supposed to be able to fly.

Because humans belong to the primate class of animals, primates can't fly, like monkeys.

It is impossible to fly even if you have wings, because people are too heavy and have too much bone density.

People can't fly because of their own limitations. But people really want to fly, so they have invented many flying tools, so that people can fly without wings.

Man evolved from apes, and then earlier, apes evolved from sea creatures, humans and birds have a common ancestor, primitive reptiles, because primitive reptiles live in different environments, in order to obtain food, some reptiles have evolved into dinosaurs, primitive black species, modern birds. While the other part of reptiles became primitive mammals like apes and humans.

The reason why humans did not grow wings was that at that time, our ancestors came down from the trees and went to the plains, where they could only strengthen their brains and hands to obtain food with their wisdom. So man did not become a birdman.

This has to be seen from the evolution of human beings, in short, people evolved from monkeys, as long as they don't fall off the tree, they don't have to worry about natural enemies, and there is no need to fly.

Because people don't have the genes to fly, and people are mammals, not birds.

Because it's not a birdman...Not to mention angels

Man doesn't have wings.

If you want to fly, you have to give all your leg muscles to your upper arms.

There is a scientific basis for this.

1. The plane cannot fly in space, but can only fly in the atmosphere, so there is no problem of hypoxia;

2. Spacecraft that can fly into outer space do not use kerosene as fuel;

3. When the aircraft flies in the horizontal direction, it does not need the lift force to be greater than the weight (that is, the thrust-to-weight ratio is greater than 1), and it is only needed when it rises in the vertical direction.

Are you asking about atmospheric aircraft or non-atmospheric aircraft?

Ordinary airplanes cannot fly into space. Those that can fly into space, such as the space shuttle, use rocket engines and have their own oxidizers. The lift of the plane to fly is greater than gravity, its lift comes from the wing, the upper edge of the wing of the aircraft is arc-shaped, the lower edge is flat, and the speed of air flowing above the wing is greater than below, so that the pressure under the wing is greater than above, resulting in lift.

When the lift is greater than the gravitational force, it can be lifted into the air.

Why do airplanes fly? Despite the fit of the individual components, the main thing is that the aircraft has a pair of wings with a special cross-sectional shape.

Wing profiles are also known as airfoils. A typical airfoil is convex at the top and flat at the bottom, and is often referred to as streamlined. According to the continuity of the fluid and Bernoulli's theorem, the air flow through the upper surface is squeezed compared to the air far ahead, and the flow velocity accelerates and the pressure decreases, and even suction (negative pressure) is formed, and the flow velocity of the air flowing through the lower surface slows down.

As a result, a pressure difference is formed between the upper and lower wing surfaces. This pressure difference is aerodynamic. According to the law of force decomposition, it is broken down along the direction of flight into upward lift and backward resistance.

The drag is overcome by the thrust provided by the engine. The lift is just enough to overcome its own gravity and lift the aircraft into the air. That's why airplanes fly.

Why do airplanes fly into the sky?