No mention of ‘meter’ being the unit of measurement, make this like saying 3:14pm is related to pi. There’s no correlation between a continuous number and a unit of measure. That’s truly apples to oranges comparison. g can easily be expressed in ‘feet’ as ~32.1 ft/s^2
A wonderful coincidence or an expected connection: why π² ≈ g
91–100 of 352 posts
Re: A wonderful coincidence or an expected connection: why π² ≈ g
#92Earlier quoted context omitted.
Doesn't the relationship hold if we change units? It seems like it must. When I worked with electric water pumps I loved that power can be easily calculates from electrical, mechanical, and fluid measurements in the same way if you use the right units. Volts Amps, torque rad/sec, pressure*flow_rate all give watts.
Nope, it completely vanishes in other units. If you do all your distance measurements in feet, for example, the value of pi is still about 3.14 but the acceleration due to gravity at the earth's surface is about 32 feet s^(-2). If you do your distance measurements in furlongs and your time measurements in hours then the acceleration due to gravity becomes about 630,000 furlongs per hour squared and pi (of course) doe…
Re: A wonderful coincidence or an expected connection: why π² ≈ g
#93Might be interesting if were true in Planck units. But also 2Pi is fundamental, who defines a ratio of something to 2 of something (radius)?
Re: A wonderful coincidence or an expected connection: why π² ≈ g
#94Re: A wonderful coincidence or an expected connection: why π² ≈ g
#95I've got a related one I like. Why are the Avogadro's number and Boltzmann's constant inverses of each other N ~ 1/k? The statement doesn't make sense because the units don't work out, but it is true in mks. It's because they multiply to the gas constant which is ~1. They both are numbers to transfer from the microscopic to human scale units and they cancel for the gas constant, which is about human scale experience…
Re: A wonderful coincidence or an expected connection: why π² ≈ g
#96This is interesting, but I have to quibble with this: > If you express this value in any other units, the magic immediately disappears. So, this is no coincidence Ordinarily, this would be extremely indicative of a coincidence. If you’re looking for a heuristic for non-coincidences, “sticks around when you change units” is the one you want. This is just an unusual case where that heuristic fails.
Doesn't the relationship hold if we change units? It seems like it must. When I worked with electric water pumps I loved that power can be easily calculates from electrical, mechanical, and fluid measurements in the same way if you use the right units. Volts Amps, torque rad/sec, pressure*flow_rate all give watts.
g in imperial units is 32 after all. g has units; pi does not
Re: A wonderful coincidence or an expected connection: why π² ≈ g
#97This is interesting, but I have to quibble with this: > If you express this value in any other units, the magic immediately disappears. So, this is no coincidence Ordinarily, this would be extremely indicative of a coincidence. If you’re looking for a heuristic for non-coincidences, “sticks around when you change units” is the one you want. This is just an unusual case where that heuristic fails.
Re: A wonderful coincidence or an expected connection: why π² ≈ g
#98Earlier quoted context omitted.
Nope, it completely vanishes in other units. If you do all your distance measurements in feet, for example, the value of pi is still about 3.14 but the acceleration due to gravity at the earth's surface is about 32 feet s^(-2). If you do your distance measurements in furlongs and your time measurements in hours then the acceleration due to gravity becomes about 630,000 furlongs per hour squared and pi (of course) doe…
Only because you're using metric seconds instead of "imperial seconds" (the time it takes for a 1 foot long pendulum to complete a full oscillation).
Re: A wonderful coincidence or an expected connection: why π² ≈ g
#99Earlier quoted context omitted.
It does not? Pi has nothing to do with our arbitrary unit system.
Pi is related to the circumference of a circle; the meter was originally defined as a portion of the circumference of the Earth, which can be approximated as a circle. "The meter was originally defined as one ten-millionth of the distance between the North Pole and the equator, along a line that passes through Paris."
Re: A wonderful coincidence or an expected connection: why π² ≈ g
#100This is interesting, but I have to quibble with this: > If you express this value in any other units, the magic immediately disappears. So, this is no coincidence Ordinarily, this would be extremely indicative of a coincidence. If you’re looking for a heuristic for non-coincidences, “sticks around when you change units” is the one you want. This is just an unusual case where that heuristic fails.
Your quibble seems nitpicky and unwarranted. What the author is saying is that the relationship becomes evident if we consider the units of m/s^2 for gravity. They just didn't quite say it like that.