supercat
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Why is kVA not the same as kW?
10 votes

When an AC line is driving an inductive or capacitive load, then the load will spend some of its time taking power from the source, but will also spend some of its time feeding power back to the ...

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Why do cars turn by turning the front wheel?
7 votes

While it might be possible to design a rear-wheel-drive car in such a fashion that the front wheels basically operated as casters and the steering was controlled by driving the rear wheels at ...

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Why use steam instead of just hot air?
5 votes

While toy steam engines often require that one pre-fill the boiler, and then only operate until the boiler is nearly empty, most practical steam engines require that every gram of steam which leaves ...

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Do contiguous laser curtains exists? and if not are there any lenses that could spread a concentrated beam into a "planar" beam
1 votes

Rather than trying to have sensors and receivers aligned perfectly, most light curtains pulse different lights and different times and then only look for signals from receivers at the moments when the ...

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Is it possible to build a perfectly spherical Prince Rupert's drop?
1 votes

After the outside of a Prince Rupert drop solidifies, it will quickly contract. During this process, if there is nowhere for the glass inside to go this will cause the outside to be under significant ...

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Why can't trains stop in 2x the distance of trucks from the same speed?
0 votes

If a train were designed to only travel in straight lines, it could be made to stop much more quickly and effectively than is possible with today's trains. Unfortunately, it is necessary to limit ...

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Why do train cars have unevenly spaced axles?
0 votes

The best kind of structure for riding along rails is a pair of axles that are held parallel to each other, and are separated by a distance roughly comparable to the space between the rails. While a ...

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