Recent content by Frodo

I have always been meaning to do this - thank you for providing the stimulus for me to do it! I have just measured a 60W bulb for a 240V supply. At room temperature it was 80 ohms. Now, if it consumes 60W when on, then 60W = 240 * 240 / R. The resistance when on is therefore ~960 ohms or 12...

Normal sea waves close to the shore behave exactly like tsunami waves. Both a 'wind driven wave approaching the beach' and a 'tsunami wave during its entire journey' are shallow water waves meaning their wave length is longer than the water depth and their speed is proportional to the depth...

The way in which the Nazerre wave is created is explained in https://www.surfertoday.com/surfing/the-mechanics-of-the-nazare-canyon-wave where the critical importance of the underwater canyon is discussed, as is how the sea floor profile causes the wave to refract. Other factors also contribute...

They may be INSULATED ELECTRICIANS SCREWDRIVER SET VDE - slotted Phillips. Note the visible taper on the driving part :-( NB - my error - it's Pozidriv, not Posidrive :mad:

From your image, the ECX head looks more akin to a Pozidriv head than to a Phillips head. Does a Pozidriv screwdriver fit it? As I recall, Phillips were introduced in the US for automated manufacturing - the driver was supposed to self align. In reality, the flanks of the driver are slightly...

See https://www.researchgate.net/publication/26386594_Relativity_in_the_Global_Positioning_System by Neil Ashby which describes in detail the multiple relativistic corrections applied in the GPS.

I think the site is being a little disingenuous so as to prove its point. It uses the example with the volume of a solid gold wreath being 51.8 cc. The volume of wreath adulterated with 30% silver would be 64.8cc, a difference of 13cc or 25%, which I think would be reasonably easy to measure...

That is correct and deliberate. I read the poster's question "When I was reading this page to understand Archimedes' 'story'" and answered appropriately by giving the story. The poster is not asking how it would be done today but is trying to understand what Archimedes did or could have done...

You may be interested in https://thestouracademytrust.org.uk/wp-content/uploads/2020/05/Archimedes-Story.pdf for a description of what apparently occurred - Archimedes realized he could measure the volume of an object by measuring the volume of water it displaced. I don't know how accurate it...

Neil Ashby's https://www.researchgate.net/publication/26386594_Relativity_in_the_Global_Positioning_System gives an excellent account of the relativistic corrections made in the GPS system. The correction for the Sagnac Effect is amusing. The design team accepted the Sagnac Effect and designed...

Dave Pax! My "spend a few minutes actually thinking about what I said " was addressed to berkeman after his put down. It was not addressed to you! Your comment was reasonable and, as you see, I agree with you. I have no disagreement with you - my disagreement is with berkeman not with you -...

I agree - "suck" is a useful concept to work with. But it is as well to understand what is actually happening whenever one resorts to a concept which isn't actually totally true. Archimedes Principle is a useful concept but the unwary will fall l into trap after trap if she uses it blindly...

Please withdraw that comment before I report you to a moderator. You have no knowledge of my academic qualifications nor of my expertise. Neither is relevant here. I seem to recall Einstein was a patent clerk when he upended the scientific world.

May I suggest you carefully read what I said before contradicting me. I said " How can the fan blade possibly affect air molecules to the left of it? It cannot attract them by gravity, electrostatic, electromagnetic means or by any other force. ". Can you perhaps tell us all how a molecule...

There is no such thing as "suck" when applied to a fluid or gas. Say a fan is set up to blow air to the right. How can the fan blade possibly affect air molecules to the left of it? It cannot attract them by gravity, electrostatic, electromagnetic means or by any other force. What a fan does...