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It's possible to obtain a sample of a gas where most of the atoms are in an excited state.
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If 2 Joules of energy is absorbed by a mass-spring system, on average 1 Joule will be in the form of kinetic energy, while 1 Joule is in potential energy.For comparison, if the mass is put into a perfectly elastic box without attached to spring, 2 Joules of energy will be in the form of kinetic energy and 0 potential energy.As analogy for temperature, the mass-spring system has twice heat capacity as the spring-less system. We can add the same amount of energy to both systems, but only half is manifested as kinetic energy in the first system, which is comparable to lower increase of temperature.The widest range of temperature measurement methods I know is by ideal gas law, which can be approached practically using monoatomic noble gases, although they start to deviate at high enough temperature where the gas starts to ionize. The electromagnetic interactions makes the energy no longer strictly in kinetic form.
Quote from: Bored chemist on 01/06/2022 11:54:09It's possible to obtain a sample of a gas where most of the atoms are in an excited state.How would you do that without increasing the temperature?
For comparison, if the mass is put into a perfectly elastic box without attached to spring, 2 Joules of energy will be in the form of kinetic energy and 0 potential energy.
Let's make the ball and the floor make perfectly elastic collision. On average, the ball has 5 Joule of kinetic energy and 5 Joule of potential energy.
If 2 Joules of energy is absorbed by a mass-spring system, on average 1 Joule will be in the form of kinetic energy, while 1 Joule is in potential energy.
The scientific answer is "Who cares? Trust me; it's possible".
The fact that you specify a perfectly elastic box means that it spends some of its time stretched.
You need to be clearer about what you are averaging over. Usually it would be an average over time - but that won't work in these examples. The bouncing ball has the lowest speed at the top of its bounce and so spends much more time there, with high potential energy and low kinetic. Similarly the mass on a spring has the lowest speed when the spring is most extended.
The bouncing ball has the lowest speed at the top of its bounce and so spends much more time there
It merely means that kinetic energy is preserved.
The bouncing ball has the lowest speed at the top of its bounce and so spends much more time there, with high potential energy and low kinetic.
Quote from: hamdani yusuf on 03/06/2022 12:30:30It merely means that kinetic energy is preserved.How?
Quote from: Bored chemist on 04/06/2022 16:46:04Quote from: hamdani yusuf on 03/06/2022 12:30:30It merely means that kinetic energy is preserved.How?That's the definition of elastic collision. It doesn't depend on how long/short the collision happens, as long as the kinetic energy of the system is preserved.
The thing about "elastic" is that, by definition, it stretches.And the only reason that kinetic energy is conserved is that it ie loaned to the surface as potential energy and then returned as kinetic energy on the rebound.So, once you know how the kinetic energy is conserved, you realise that, ironically, it isn't. Briefly, it is converted to potential energy.Did you not realise that was why I asked "How?" ?Instead of answering the question, you posted some nonsense about duration.
In an ideal gas, all collisions are perfectly elastic, by definition, and therefore the rebound is instantaneous..
Which is why we distinguish between real gases and ideal gases. In the GCSE fantasy world of weightless strings and frictionless pulleys, all gases are composed of tiny billiard balls and PV = RT for ever.
from which we infer that temperature is a measure of the mean internal kinetic energy of a body