Recent content by David VH

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    Bicycle tire width vs. pressure for identical comfort

    @russ_watters you are correct, I intend to undo the comfort advantage of the wider tire in exchange for lower rolling resistance. If the increased width brings a comfort advantage at least... Right now it's not even confirmed that a wider tire at the same pressure is more comfortable, but I...
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    Bicycle tire width vs. pressure for identical comfort

    @anorlunda tires are expensive though, I was trying to get a better picture of what I would be getting for my outlay before I decide to do it. Maybe I should do it in the interest of science, no matter the cost. I neglected stiffness but I'm aware that's how it works :) What do you think of...
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    Bicycle tire width vs. pressure for identical comfort

    Here is what I want to know specifically: if I replace my 5cm wide rear tire with a 6.25cm wide tire, how much can I increase the inflation pressure to obtain the same comfort? I realize "comfort" is not a quantifiable measurement, maybe shock absorption characteristics is better. Perhaps it...
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    A ball struck by a cue in billiards with English goes straight at first....

    This video may be of interest to this thread: The most interesting part IMO is around the 5:55 mark where consecutive shots are being performed, depleting the chalk from the cue. You can see that the cueball deflection from the cue direction exceeds 1 degree, time after time. From this video...
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    A ball struck by a cue in billiards with English goes straight at first....

    It is both. If you forget to chalk before a significantly off-center shot, you risk a miscue. It's easy to forget how long it's been since you chalked it, so many players have developed a habit of chalking while they plan the shot so they never forget, turning it into a ritual. 90% of billiard...
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    A ball struck by a cue in billiards with English goes straight at first....

    Think of it as adding gradually less important factors (or terms...) to the model. The basic model is a cue and cueball made of frictionless adamantium, in a vacuum, without bridge hand. This is the 15 degree scenario from the first page, and the cue would bounce off to the side uninhibited. But...
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    A ball struck by a cue in billiards with English goes straight at first....

    I am lost. I thought this was the discussion we were having: - if there were no friction between cue tip and cueball and both were undeformable, the cueball would go 15 degrees left of the cue direction; - there is friction in the contact, causing the force to be mostly imparted in the...
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    A ball struck by a cue in billiards with English goes straight at first....

    How did you come to the 1 degree (could be correct, I don't see all the relevant math in my head)? 1 degree is enormous for a snooker player by the way. For a not-that-hard half table shot of ~1.7m a 1 degree deviation is more than the radius of a snooker ball, in other words the difference...
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    A ball struck by a cue in billiards with English goes straight at first....

    As an aside, as far as I know there are two distinct reasons to play with side (English). First is to swerve the cueball around an obstacle. The motion has two phases, first it goes fairly straight as it slips over the table, then it slows down and as it starts rolling, the side "takes" and the...
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    Is Tony Stark's Genius Realistic?

    How many bits of information does one have to digest before being an expert in thermonuclear physics? How many bits of information can a regular person digest in one night? If such calculations were possible, we could rate his superhuman intelligence against superman's strength for example. But...
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    Help Kathy Write a Book on Electricity & Tesla: What's Missing?

    What a fabulous article. The URL should give the bias away and it's full of unsubstantiated claims of its own, but it does show very well what the difference is between on one hand these two entrepreneurs (Edison & Tesla) who wanted to be heroes to the public and on the other hand the multitude...
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    How to Salvage my Academic Career?

    Without intending to be mean, all I read in this topic is "it's complicated" and "trouble follows me around". I think it would serve you well to uncomplicate (is that a word?) things. No one wants to hear things like "for personal reasons I do not wish to divulge", serious. Just own the...
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