## Hunus 3 years ago Question

1. Hunus

In one of Linus Pauling's books he poses a problem on how much the temperature of 1kg of water will rise as it travels from the top of Niagra Falls to the bottom. My question is does the temperature rise? I thought the loss of potential energy was transferred into kinetic energy, not thermal. Can someone clarify?

2. Mani_Jha

The temperature does rise. The first law of thermodynamics states that "Work is heat, and heat is work". You'll notice that if a body moves with a high speed, it becomes hotter. Thermal energy is, after all, the kinetic energy of the particles inside the body. So, when kinetic energy increases, thermal energy does too.

3. Hunus

I thought alot of the heat was as a result of collisions with the air molecules. So the energy is both kinetic and thermal?

4. Mani_Jha

Yups. Air resistance also heats it up, but very slightly.

5. Hunus

So as an object approaches the speed of light and it's energy grows larger and larger, the object's temperature is growing very large as well?

6. Hunus

Like not a particle tending toward the speed of light, but a rigid body.

7. Mani_Jha

Well, that is not possible, but assuming that it is, yes, the temperature will grow too

8. Hunus

Okay. Thank you. You seem very knowledgeable when it comes to physics.

9. Mani_Jha

Well, Physics is my favourite subject, but I am still in the process of learning it. ;)

10. Hunus

It's mine too. Is that what you're majoring in?

11. Mani_Jha

lol, I am still a high school student!

12. Hunus

That's ridiculous. In a good way. I've thought you were a college student!

13. Vincent-Lyon.Fr

During the fall, the PE will be converted to macroscopic kinetic energy, and the temperature of the water will remain unchanged. But when the water crashed at the bottom, the macroscopic KE is transformed into microscopic KE. This increase in µ.ic KE produces the temperature rise.

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