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This is a really interesting question. It turns out that your body is reasonably conductive (think salt water, more on that in the answer to this question), and that it can couple to RF sources capacitively. Referring to the Wikipedia article on keyless entry systems; they typically operate at an RF frequency of $315\text{ MHz}$, the wavelength of which is ...

15

It can't be from the moisture in the air. If there was enough moisture in the air to produce condensation then it would be condensing on everything. There would actually be less of it condensing on the tailpipe, because the tailpipe is quite warm. In fact the water is generated by the combustion of the fuel in the car. It comes from the hydrogen in the ...

5

The noise is either from the AC electricity, which would be a 60Hz buzzing, or from small bubbles forming on the heating element itself. When the electricity stops, both the buzzing and the bubble formation will stop as well. Bubbles create sound due to quickly expanding from a small nucleus. Here's a book I found with a section on noise from bubble ...

5

Remote "key fob" designers intentionally limit size so they conveniently fit in your pocket. However, the convenience comes at a big price - the tiny loop antenna inside is extremely inefficient, transmitting less than 10% of the energy pumped into it, while the rest is simply converted into heat. When holding your remote to your head, your arm, shoulder ...

5

The way it works has nothing to do with your body. Remotes have their antenna as a more or less circular trace on the board (a loop antenna). The strongest signal is when the top or base of the remote is pointed at the receiver. The weakest signal is when the fob is pointed 90 degrees away, such as when pointing it like a TV remote. Guess which way most ...

3

This is something we must all have observed, but I don't know of any definitive study. In the absence of hard data I can think of three potentially relevant effects: Dielectrics, like the human body, deform electromagnetic fields in their vicinity The wavelength of FM radio is around 3m and therefore comparable to the size of a typical human. This means ...

3

The circles are droplets of fat (triglycerides: triesters of glycerol and fatty acids). The two phases (water and fat) are immiscible because the water molecules are more attracted (hydrogen bonded) to each other than to the fat molecules. Absent gravity, energy would be minimized by the droplets being spherical, but gravity flattens the droplets. The ...

3

If you assume that Your body is a uniform, thin rigid rod. One end of the rod is pivoted (aka your feet) during the fall. Then one simply recalls that the angular velocity $\omega$ of rotation of your body is related to the tangential velocity $v$ of a point a distance $r$ from the pivot by \begin{align} v = \omega r \end{align} Now, if you have height ...

3

The Bernoulli equation, with friction, has the following form: $$p_1+\frac{1}{2}{\rho}v_1^2+{\rho}gz_1=p_2+\frac{1}{2}{\rho}v_2^2+{\rho}gz_2+\left(f\frac{L}{D}+{\sum}K\right)\frac{1}{2}{\rho}v_2^2$$ where $p$ is pressure, $\rho$ desity, $v$ velocity, $z$ height, $g$ the acceleration due to gravity, $f$ the friction factor, $L$ the length of the tube, $D$ ...

3

This is quite humorous. In an 1883 offical US military publication, "Weather Proverbs" by 1st Lt. Dunwoody, at page 107 it is stated "When coffee bubbles collect in the centre of the cup expect fair weather. When they adhere to the cup, forming a ring, expect rain." This is the converse of the lifehack proverb! In 1997 Dave Thurlow, using a grant ...

3

Pretty much no. The problem is that you are not (pardon me :-) ) a rigid body, so you're going to feel a certain amount of force from the wind regardless of what sort of weights you're carrying. What can help is walking with your feet farther apart, which gives you a more stable base to work from, and to learn to turn your body sideways to the wind as ...

3

Yes, and in fact there are several types of electrical chargers that you power by walking. Typically you'd use these for low power applications such as recharging your mobile phone as you walk. There are a lot of frankly daft designs out there, but this one is being funded by the US military, which may or may not be daft depending on your views of the ...

2

I assume your car is front wheel drive. The phenomenon is simply Newton's third law in disguise. The car exerts a torque on its forward axle and the wheels exert the same magnitude, opposite sense torque on the car. Normally, the torque is not so big, because as soon as it is exerted on the wheels by the car, the wheels push backward on the road and the ...

2

This is due to Rayleigh scattering, i.e. the shorter wavelengths (those near the violet end of the visible spectrum) are more deflected by dust particles than the longer wavelengths (those near the red end of the visible spectrum). When the sun is near the horizon, it the path of the light through the atmosphere (and in particular through layers which have ...

2

Depending on the bulb, the bulb has two circuits. The first circuit (across the two posts at either end) heats a filament at either end to vaporize mercury from an amalgam pellet reservoir behind a small metal shield under the filament. The second circuit is through the tube, the mercury vapor discharge with negative resistance, regulated by the ballast. ...

2

This sound is most likely caused by the choke coil which is inside the lamps housing. It is needed for lamp starting and operation. Starting works like this: After initially the starter circuit allows for current flow through the heaters in the tube, it interrupts the the current after an initial period. This causes a high voltage impulse to be created by ...

1

A little bit of physics - but mostly just fashion. Red wines (supposedly) need to oxidize to release the flavo(u)r so red wine glasses have wider necks to allow more air. White wines don't and so the glasses have narrower necks. If there really was a significant difference then you would drink white wines from a sealed pouch through a straw and shake red ...

1

The electrical energy you pay for doesn't just go into the appliances; some amount of it ends up as heat in the electrical path from the meter to the loads. Also, heat from a load such as a heating element can travel along the electrical conductors away from the application (the water tank) - remember: most good electrical conductors are also good thermal ...

1

Unplugged ears let in background noise, which is considerable and perpetual in cities. If you venture into isolated rural land, a cave, or an anechoic chamber, you can hear silence. It is a very different environment. Here is an experiment! A dental cavity being drilled is disturbing for the high-pitched whine of the drill. Try wearing a pair of foam ...

1

Psychoacoustics is a fascinating and difficult field. For a simple example: many people, myself included, perceive music thru headphones as originating somewhere in the back of our skull. Same music from stereo speakers comes from "the room." So... your earplugs may well be providing a direct mechanical conductive path from jawbone, ear mass, etc. for ...

1

Three guesses: Light is composed of zillions of photons, elementary particles which even though have zero mass carry momentum. p is the momentum , h is Planck's constant, c the velocity of light, nu is the frequency In the link you gave one sees that the ping sound comes at a delta function in time of a lot of light. My first guess is that the ...

1

An arbitrary periodic signal can be decomposed into a sum of pure tones of varying amplitudes and phase. This is called Fourier decomposition. So, for example, a sawtooth waveform, much like that produced by a violin, has many frequency components of distinct amplitudes and phase. The loudspeaker simply reproduces the sawtooth waveform. It isn't ...

1

If you understand that a car can topple while negotiating a sharp turn at high speeds, then you just have to consider the fact that skidding happens when the tyres don't have enough grip to prevent the car from being thrown out the trajectory. Newton first law states that any solid tends to continue in a straight path, so the solid has to be pulled ...

1

If you're asking whether it is impossible to skid while turnning at all, I have a tree in my front yard (well, my parents' front yard) that says that it is. Just imagine the case where friction goes to zero (for example, there might be a layer of ice on the road.) If you're asking whether the path will be circular, just note that if you don't move the ...

1

Yes, your thinking is correct, and the water is a byproduct of combustion. Let's examine what happens. Many combustion reactions involve reacting hydrocarbons with oxygen. Hydrocarbons are any molecule consisting of hydrogen, carbon, and sometimes oxygen. The byproducts of these are always CO2 and H20, so carbon dioxide and water, or the infamous dihydrogen ...

1

In an ideal gas where P is the absolute pressure of the gas, V is the volume of the gas, n is the amount of substance of gas (measured in moles), T is the absolute temperature of the gas and R is the ideal, or universal, gas constant. The capped gas in the bottle cools, according to the black body radiation law everything cools at a certain rate. ...

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