Why do grandfather clocks keep going? The only way I see htis working is if the chamber has no air (vacuum).
In the absence of any kind of friction, it would never lose energy, so yes, in theory. Of course, no real pendulum can ever be totally free of all friction, so no, in practice.whozum said:Slightly deviating: Provided a simple pendulum in vacuum, would it swing forever? Close to?
Precisely.whozum said:Im saying putting it in a vacuum, as close a vacuum as possible. There will be an extremely small bit of friction from possibly stray air molecules, and some from the junction of string and ceiling.
Sure, you can spend some engineering effort to design a pendulum support that will allow the pendulum to lose only a specified amount of its energy in a specified time. For example, you could design a pendulum that would only lose 1% of its energy to friction in a week, but that design will be more difficult than one that loses 10% of its energy in a week. There is, however, no practical way to design a pendulum that never loses any energy.My question is in a practical sense, are those small enough to neglect for a certain time (that is reasonable for a clock of such delicate construction) before recalibration? I'm talking at least a week or so. We can attribute the error in the correct time to the energy lost in friction.
The period does not stay exactly the same when its displacement changes. That approximate relationship is due to taking the "small angle approximation" of the sine function:But even if some energy is lost, is the period of a pendulum not the same regardless of the displacement from equilibrium? If not, perhaps we could adjust our detector to compensate for such effects?
Cheers for that Mr G, I like the cut of your jib. But not a grandfather clock...FredGarvin said:Here you go Brewnog...The anniversary clock has a rotating pendulum. Those aer the ones I was referring to.