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13

Different parts of the eye have different response speed. The corner of your eye doesn't see color, but is fast; the center sees color, and is slower. This means that when you look at a 60 Hz monitor straight-on, the image is perfectly steady; but when you look at it from the corner of your eye, it is flickering. As you go to even higher frequencies of ...


7

The cochlea has a complex physical structure, with multiple membranes and fluid-filled chambers. Therefore to explain the separation of frequencies along the basilar membrane of the cochlea is complex to. Sure, there are a lot of very general descriptions (even the answer of theblackcat) and a lot never go into the actual physics of the system. This ...


7

Short answer: mostly no. Slightly longer answer: the interaction of neutrinos with the molecules of your body take several forms, but they all come down to ionizing dose. However, there are many larger sources of ionizing dose in your like. Things like the Potasium-40 in the food you eat, radon and Carbon-14 in the air you breath, cosmic rays, and on and ...


4

This is not true. The rumor comes from a paper written in the 30s. The scientist, Antoine Magnan, who made the paper did his calculations wrong and retracted the paper, but, of course, the media wouldn't listen.


4

1&2) Let's suppose there are only two forces in play: the one exerted by the man, and weight. The sum of works done on the body equals the variation of kinetic energy (this is a theorem of mechanics; I fail to find its English name). Since the body has no velocity at the start and at the end, the sum of works is zero. The net work done by the man on ...


3

No animal, object or person defies gravity. Not here on earth, not in any place on the universe. Ask yourself this question on another form: When a plane, or a bird, flies, is he(it) defying gravity? No! They are just balancing forces, pushing air behind then, so it can compensate their weight. The direction of the resultant vector of forces combined, is up. ...


2

As yet unknown - there are some hints that life might exist ie methane emissions, but no proof.


2

If you ignore air resistance, and assume the surface is hard and absorbs no energy that you need to care about, then the remaining energy must be absorbed as heat in your body (and shoes). If your temperature is steady then you will lose energy through heat radiation and convection at the rate you use it. There will be many different chemical and mechanical ...


2

If bumblebees were propelled the way fixed-wing aircraft are propelled, their wings would not be aerodynamic. An airplane needs two devices to become and remain airborne. Its engines generate thrust, and its wings provide lift. A bumblebee, however combines both thrust and lift into one integrated device. The bumblebee's wings, unlike a fixed wing ...


2

There is some interesting data on the subject. People looked at the relationship between the prevalence of radon in counties in the US with the mortality due to lung cancer, and found a surprising relationship. Instead of the "more radon kills more people" correlation that was expected, there was an initial "dip" in the curve - as though "a little bit of ...


2

1) What can be say about the work done by the man to the weight? Unlike gravity, the force exerted by the man is in general not constant, does not depend only on position of the body (you may apply different force on the weight at the same height $h$ on the way up vs. on the way down), and is not conservative (does not arise from a potential). When the ...


1

The conscious part of the human brain cannot process visual information that persists for less than about .04 seconds while the subconscious part is thought to be faster. What the brain is doing is pattern recognition in either case (which requires a considerable amount of mental processing). The issue is how long does this mental processing require and the ...


1

Oh, I love this subject. The term here is radiation hormesis, and it's basically off-limits for nuclear regulators (If it's true, it horribly complicates the risk analysis for the use of any radiation source). The classic study comes from Taiwan http://www.jpands.org/vol9no1/chen.pdf where a number of apartment buildings were built using rebar that had been ...


1

The potential difference between the two points on the wire is negligible at all times but initially there's a potential difference between the wire and the bird and there would be a (very short lived) transient current which is similar to electrostatic discharge you feel when you touch an object with electrostatic charge build-up.


1

Perhaps I could share some idea for further research. If we could make actual and correct pressure measurements in the cochlea to reveal wether the non-stationary Bernoulli effect is a good description of the actual physics-of-how-the-cochlea-isolates-frequencies-along-its-length? I would consider: I would propose to use a pitot tube, with sensor in the ...


1

One way the body uses to lose temperature is by sweating. If the humidity of the environment is high, the the sweat can't vaporize(the environment won't accept it) and thus the water on the body gets warmer and we feel even more awful. But there are other mechanism by which the body loses energy and thus temperature. One of the main mechanism is via ...


1

For our three compartment hearing sense, from a physics point of view, there is a basilar membrane stimulation, from base to apex, in its pathway in the cochlea, to a place on the basilar membrane. By periodic movement of perilymph, non viscous fluid, backwards and forewards, in the cochlear duct meet the conditions of a potential flow. The basilar ...


1

If two twins (or clocks) decide to go live in differently strong gravity wells, they will age at different rates. It isn't based on where you were born. In particular it is not just that different planets spin at different rates or orbit their stars at different rates. Clocks just tick slower in a deeper gravity well. Hearts beat slower. Synapses fire ...


1

What is the potential energy of the human body? 36 MJ $\simeq$ 8600 kcal. The basal metabolic state for a human is about 60 W. Let's assume (horrible) an immobile person dies after one week (604800 s) of starvation, he will have consumed 60 W * 604800 s = 36,288,000 J. Where does this energy come from? from the high energy chemical bonds of ...


1

The definition of entropy can be found on Wikipedia. It's the integral of the reversible heat flow divided by the temperature at which the flow occurs. This has, at face value, nothing to do with order and disorder because there is no obvious way to even define structure in thermodynamics. One has to understand the link between thermodynamics and ...


1

The heart only acts as a big dipole, when it is electrically active. ECG measures the potential difference between different places on the skin. These potential differences are created when different parts of the heart muscle are in dfferent stages of their action potential. For example, when the septum and the subendocardial myocytes are depolarized, but ...


1

It has been found that gravity, understood as force, acts on any body of any shape or material depending only on the mass of the body. In fact, gravity understood as the curvature of spacetime acts on all of matter and energy, including light. In this way, nothing defies gravity: it is one of the most universal phenomena known to man. Colloquially, one ...


1

The correct statement is - the total work done on the weight is zero i.e. the total energy of the weight before and after the experiment is same. However, when the man is lifting the weight he is obviously working against gravity. More importantly, when he is lowering the weight, he is still working against gravity, as gravity would rather lower the weight ...



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