Physics quiz questions

1.Shut up and plug your ears with your hands, you know why.

Because there is a eustachian tube passage from the human mouth to the inner ear, the mouth is quickly opened when encountering a loud noise, so that the pressure inside and outside the eardrum is the same, and the eardrum is prevented from being damaged loudly.

2.It is convenient to accept the sound and at the same time judge the ** of the sound.

3.There is no contradiction, stereo sound is the use of human binaural effect, so that the horns in different directions are different in the performance of the same sound, so that people have the effect of sound.

4.The singing voice that I usually hear is transmitted to the inner ear through several ways such as skulls and air, and the frequency is more abundant. The sound recorded by the recorder sounds only through the air, and some frequencies are not capable of reproducing the sound of the recorder. So it doesn't sound the same.

1. Sound waves can produce pressure, because sound waves are the vibration of the atmosphere, and when the sound waves are large, if the pressure difference between the inside and outside of the eardrum is too large, it is easy to cause damage.

2. Make the ear hole face the direction of the sound so that you can hear it more clearly.

3. No contradictions. Stereo sound is the simulation of different sound source characteristics to give the human ear an illusion.

4. Because when you listen to yourself, the sound is transmitted through the body in addition to air transmission, and the effect of air transmission can only be heard in the tape recorder, so it is not exactly the same.

The first one belongs to living beings, which should be conditioned reflexes.

The second one doesn't quite know.

The third is not contradictory, the sound will be reflected.

The fourth one either had a broken tape recorder, or the girl's voice was out of range.

4.In fact, what you say and hear is different from what others hear.

No, according to Xiao Ming's method, "my starting line is 10 meters back", then the 60-meter sprint race becomes Xiao Ming's 70-meter, vigorously 60-meter sprint race, and the result will not reach the finish line at the same time.

According to the method of vigorous force, "my start is moved forward by ten meters", then the 60-meter sprint race becomes a 60-meter sprint race of Xiao Ming and 50-meter vigorously, and the result is to reach the finish line together.

Run according to the method Xiao Ming said, Xiao Ming will reach the finish line first.

No, it's an acceleration issue.

In the case of constant potential energy, the faster the speed of the object has greater kinetic energy, water under high pressure to obtain a huge kinetic energy, because the water flow is very fine, so when the object is touched again, the kinetic energy converted into the elastic force of the action point is very concentrated, the elastic force converted from the conversion is very huge, enough to break the stone and divide the gold.

After adding the abrasive material, the part of the object in contact with the waterjet is deformed under the action of the waterjet, and a part of the abrasive material will rub against the object, thereby accelerating the ability and speed of the cutting object. In addition, after adding the abrasive abrasive, the water flow density increases, the kinetic energy at the beginning is greater, the energy conversion is more, and the effect is naturally more obvious.

This is because the pressure of the fluid is related to the flow velocity, the faster the flow rate, the lower the pressure, and the slower the flow rate, the greater the pressure.

In the part where the table tennis ball is close to the water column, the water flow speed is faster, and the pressure on the table tennis ball is smaller. In the part where the table tennis ball is far away from the water column, the water flow speed is slower, and the pressure of the table tennis ball is greater. Therefore, the type of lead ,—— ——— of the wilderness

g A = m A g = 1*

pA=FAA=gAAS A=

Platoon'After A and B are cut off and superimposed, the pressure on the horizontal surface becomes larger, and their increased pressures are δp A and δp B, respectively.

PA=G AA (HA(HA-H))-G AA HA2=PAH(HA-H)).

p B = g B (h B (h B - H)) - g B h B 2 = p B h (h B - h).

Because pAH (HA-H) and PA=PB.

So PA + δPA is PA'< pB'