Physics Why is this statement wrong? Mechanical waves have both transverse and longitudinal waves, w

Transverse waves, the direction of vibration and the direction of propagation are perpendicular.

Longitudinal waves, the direction of vibration is the direction of propagation.

Wrong, electromagnetic waves.

Electromagnetic waves are transverse waves. The direction of propagation of magnetic fields, electric fields, and waves is perpendicular to each other in space. Transverse wave.

In terms of mechanical waves, such as sound waves, longitudinal waves are typical. For example, striking a gong with something. The direction of vibration of the gong and drum is the same as the direction of propagation of sound waves. Longitudinal wave.

Transverse waves, such as hitting a stone in water. A large number of particles in the water are forced downward and off the equilibrium position. Vibrates up and down, and drives the surrounding water molecules to vibrate. Then the water waves spread horizontally. Transverse wave.

Longitudinal wave type: When the vibration direction of the particle in the medium is consistent with the propagation direction of the ultrasonic wave, this wave is a longitudinal wave wave type.

Shear wave pattern: When the vibration direction of the particle in the medium is perpendicular to the propagation direction of the ultrasonic wave, this wave is a shear wave pattern.

The propagation of mechanical vibrations in a medium is known as mechanical waves.

Mechanical waves are both similar and different from electromagnetic waves, mechanical waves are generated by mechanical vibrations, and electromagnetic waves are generated by electromagnetic oscillations; The propagation of mechanical waves requires a specific medium, and the propagation speed in different media is also different, and it cannot propagate at all in a vacuum, whereas electromagnetic waves (such as light waves) can propagate in a vacuum; Mechanical waves can be transverse and longitudinal waves, but electromagnetic waves can only be transverse waves; Many physical properties of mechanical waves and electromagnetic waves, such as refraction, reflection, etc., are the same, and the physical quantities that describe them are also the same.

Sound waves are mechanical waves.

The vibration of the sound source causes the surrounding air to oscillate, and that type of oscillation is called sound waves. Sound travels in the form of waves, which we call sound waves. Sound waves travel in all directions with the help of various mediums.

In the air of an open space, the propagation is like a soap bubble that gradually blows up, a spherical array wave. Sound refers to the special case of audible sound waves, such as the audible sound waves of the human ear, when the array wave reaches the position of the human ear, the human auditory organ will have the corresponding sound perception.

In addition to air, water, metal, wood, etc. are also capable of transmitting sound waves, and they are all good mediums for sound waves. In a vacuum, sound waves cannot propagate.

A sine wave is the simplest form of wave. When a high-quality tuning fork vibrates, it produces a sinusoidal sound wave.

Sine sound waves are pure tones. Any complex sound wave is a composite wave formed by the superposition of multiple sine waves, which are compound sounds that are different from pure tones. A sine wave is the basic unit of a variety of complex sound waves.

Loudspeakers, various musical instruments, and the articulatory organs of humans and animals are all sound source bodies. **Objects that can move, such as an epicenter, a flash power, raindrops, wind, windy leaves, insect wings, etc., can be sound source bodies. The sound waves they cause are all more complex than sine waves and belong to complex waves.

Produces a variety of complex fluctuations, including sound waves, which are actually inaudible to the human ear and whose frequency is too low (e.g. 1Hz).

X-rays are a type of electromagnetic wave, but X-rays are not waves of matter.

Mechanical waves include transverse waves (water waves) and longitudinal waves (sound waves); Electromagnetic waves are transverse waves and do not have longitudinal waves.

False: Electromagnetic waves have both transverse and longitudinal waves.

The mechanical wave is correctly described.

Electromagnetic waves are only transverse waves.

Water waves are neither transverse nor longitudinal.

The shear wave vibration and propagation direction is perpendicular, and the longitudinal wave vibration and propagation direction is horizontal.

However, when water waves propagate, they are neither vertical nor horizontal, so water waves are neither transverse nor longitudinal.

No, there are only two kinds of waves.

There are indeed different ways to classify waves:

According to the mechanism of wave generation, it is classified as follows: one is mechanical waves, and the other is electromagnetic waves;

According to the form of wave propagation, it is divided into: one is a transverse wave, and the other is a longitudinal wave;

According to the length of the wavelength, it is divided into: long wave, short wave, mechanical wave has a longer wavelength, electromagnetic wave has a large wavelength range, there are long and short waves.

BC don't be too lazy, draw a picture in four seconds, draw a picture in 7 seconds, and draw a picture in six seconds.

In the beginning, the origin 0 starts to propagate the transverse wave to the right, in fact, there are two times, it should be noted, one is the transverse propagation time and the other is the longitudinal propagation time.

You can build a Cartesian coordinate system with point o as the origin, and then to the right, assuming that there is a point every other meter (in fact, it should be continuous, just to make it easier for you to understand), and when the wave source sends out the signal of the wave, the first point (located at x1, our assumption is equal to one meter) receives the signal at the end of the second, so this point starts to vibrate up and down. Then, at the end of two seconds before the start of the timer, the second point (at the point of x2, which is two meters in our hypothesis) starts to vibrate up and down. At the end of the third second, the point at point A also received the signal and began to vibrate up and down.

After another second, the point rises to the crest of the wave, which is also its first crest (coordinates x3,y), and at the same moment, the point at position b receives a signal (coordinates x4,0), which happens at the end of the fourth second. At the end of the fifth second, the point at position A returns to the origin (coordinates x3,0 at this moment), the point at position B reaches the peak (x4,y) and the point with a distance of origin 5 begins to move upwards (at this time D can be excluded), at the end of the sixth second, the point at position A goes down to the trough (x3,-y), the point at position B returns to the original position B (x4,0), and the point at a distance of 5m from the origin point has obviously reached the first peak. At the end of the seventh second, B reaches the first trough (x4,-y).

In fact, the origin sends a signal to the right, and each point that receives the signal starts to move up and down, which is called a bola.

So, looking at a, the wavelength of this wave is 2 meters. In fact, we saw earlier that at the end of the sixth second, position A is at the trough, and the 5m place is at the crest, so the distance between this is obviously half a wavelength, because the wavelength definition is the distance between two troughs or crests, and 2 meters is just the distance between a trough and a crest, in fact the wavelength should be 4 meters.

The b-cycle is four seconds. This is obviously correct according to our establishment, just look at point A, one second up, one second back, one second down, one second back, these four seconds just form a cycle.

c, the wave velocity is 1m s. Obviously, this is also true, this wave speed is the lateral speed I said at the beginning, and our 1 is obviously 1m s.

d has been ruled out.

That's why I should choose BC.

Got it? o Point is nothing more than the origin of the coordinate system, and you can see it by drawing a diagram.

1.The distance o point refers to the distance of wave propagation, and the key to this problem is to find the period and wave velocity.

2.It can be obtained using 4=3 v+t 4 and 7=4 v+3t 4: t=4, v=1The wavelength is 4

t=5 Answer: bc

Forget it, I'm too lazy to fight with you, as long as the answer comes out, I'll just waste 20 minutes in vain as a workout typing and comprehension questions.

BC don't be too lazy, draw a picture in four seconds, draw a picture in 7 seconds, and draw a picture in six seconds.

The mechanical wave propagation must have a medium, the reason why there are water waves and the wavy shape of the rope is because their propagation medium is different, the mechanical wave on the rope can propagate backwards along the rope, and the waves in the water are propagated along the water surface, so the shape of the wave has a lot to do with the medium, the waves on the seaside are layer by layer, and the waves in the pond are circle by circle. If you put the vibration source that generates the waves on the rope on the surface of the water, the waves it produces will be a circle of waves.

Let me explain to you that when the water waves come to the slit, a short stretch of water will act as a new source of vibration behind the slit, and the resulting wave will have the same frequency as the surface of the water at the slit.

First of all, we must understand what a mechanical wave is: -- A mechanical wave is the propagation of mechanical vibration in a medium, then you will know what the wave propagates === It is a mechanical vibration that propagation. How to propagate, drive each other, have you seen a wave of people when you have watched a sports game, that is a demonstration of mechanical waves, which forms of wave propagation you mentioned, about diffraction === when the wave propagates the obstacle?

or seams), it drives the pointing point of this place to start to do mechanical vibration, and the vibration of the particle of this place (obstacle or seam) drives the vibration of other particle points, which becomes a new wave source, and continues to propagate to the surrounding area, forming the diffraction of the wave.

It can be understood as spreading in all directions, which is more common.

As for why it can pass through the slit, it can be understood that at the slit, the wave creates a new source of the same amplitude and frequency as the wave source. Bypassing an obstacle can also be understood in this way, creating a new wave source at the edge.

That's what I understood then, and that's how I understand it now, and there is no problem.

The point where the wave travels is vibrating. When the wave reaches the aperture, the point at the aperture propagates outward as a vibration source. That's how I understood it at the time. I've forgotten it for a long time.

The process by which vibrations propagate outward along the medium is called waves.

According to the spatial relationship between the direction of vibration and the direction of propagation, the wave can be divided into transverse wave and longitudinal wave, and according to the properties of the wave source, the wave can be divided into mechanical wave and electromagnetic wave, among which, electromagnetic wave only transverse wave.

Regardless of the type of wave, the frequency of the wave is determined by the wave source and is independent of the medium; The speed of propagation of a wave is determined by the medium and has nothing to do with the source of the wave.

Waves with long wavelength and low frequency have obvious diffraction phenomena and can bypass larger objects and propagate to distant places; Waves with short wavelengths and high frequencies have weak diffraction and good directionality.

Longitudinal waves, transverse waves do not necessarily refer to mechanical waves. Electromagnetic waves are transverse waves.

Electromagnetic waves are generated by alternating electromagnetic fields perpendicular to each other, and the direction of propagation is perpendicular to the direction of the electric field and the direction of the magnetic field!

A correct. It can be seen from the vibration image that the period is T=, the wave propagating to the right at a and the wave propagating to the left at B meet at point C at T1 s, T1=, A and B are 6 m apart, so the two waves each propagate 3m to meet, and each wave propagates a wavelength, so the wavelength is 2m, and the wave velocity is 10m s;

b error. Same reasons as above;

c error. From the vibration image, it can be seen that the vibration direction of the two columns of waves is opposite, and when the two vibration directions are opposite when transmitted to c at the same time, the search vibration is weakened.

d correct. At the T2 S moment, the source of B itself is in the equilibrium position, and the vibration from the source of A is in the same position as the vibration of the leakage, and it is still in the equilibrium position when superimposed.

Common mechanical waves are: water waves, sound waves, and ** waves.

The propagation speed of sound in the air of 15 is 340m s, and electromagnetic waves are light waves, and all light belongs to electromagnetic waves, such as: radio waves, infrared, and visible light.

The propagation speed of light in a vacuum is 3 10*8m s, and the speed in air is only slightly less than that of a vacuum, but it is also said to be 3 10*8m s.