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The pitch of the sounds start high and end up low. Is this some kind of doppler effect? No. This is chirp induced by dispersion, which is the acoustic version of the same phenomenon for light. This refers to the fact that, generically, sound waves of different frequencies travel at different speeds. This can be caused by the material properties of the ...


14

This phenomenon is known as Acoustic Dispersion. Acoustic dispersion is the phenomenon of a sound wave separating into its component frequencies as it passes through a material. This happens because the phase velocity of a sound wave is a function of frequency in a dispersive media $^{\dagger}$. Much similar to how electromagnetic waves disperse when ...


11

First of all, let's analyse the effect of the shaft in a particular circular cross-section. When the shaft of the motor rotates, it causes the water surrounding it to revolve around the shaft in a circular path. The flow rate of water near the shaft is more than that away from it. This is a consequence of viscosity of water. According to the Bernoulli's ...


3

The mechanical energy needed in both cases to lift the body will stay the same. You say "Arguments for reducing: When you raised your legs, your center of gravity moves a shorter distance, thus you use less energy to hoist your body up". This is not true. Once you have lifted your legs, your center of gravity will be higher to start with, but the movements ...


3

It is the same principle as applies to an arch. The curve of an arch is such that forces are transmitted along the curve of the arch. Ideal curves for this are the catenary arch, and for a bridge supporting weight, the cycloid, most famously used in the "New" London Bridge (1831–1967) The difference with an eggshell is that it is a 2D surface in three ...


2

Easier to walk when there’s a curve. Otherwise the sole has to bend every time a step is taken. This will damage it over time.


1

The observations in the linked question are unreliable because it is not clear whether electrical or thermal resistance has been measured. A simpler explanation for your observation is that when you increase the heat supply gradually you are allowing more time for heat to be conducted away from the base of the pan. The base of the pan is very hot for a much ...


1

I turned down the heat and the bubbling stopped after a while You are still heating, it means that the cooling happening at the top level keeps the water below boiling point. The level of noodles going down, reduces the volume to be heated from the full pot to half of the pot, so the heat supplied is enough for the water below the noodles to reach the ...


1

How these thermometers works is based on the principle of blackbody radiation and the Stefan-Boltzmann law. There is an IR sensor housed inside the thermometer that senses the total power radiated in a window of IR. And this power is related to the temperature of the emitter. But there is also a dependence on emissivity which is governed by the material ...


1

As asked, I'll keep it simple. An echo can not amplify sound, so your wall will never amplify. If the wall is closer than 17.5m or a close figure, it is impossible for you to hear a resound. If it's not so close, there is a possibility you will hear faint echoes but not strong enough to disturb you. Because in an open space like that, waves scatter and sound ...


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