4 ms·
> The gravitational force doesn’t change based on your kinetic energy. This is not correct. Gravity is a function of everything that has energy (see the stres
by Xcelerate 6y ago
> The gravitational force doesn’t change based on your kinetic energy.
This is not correct.
Gravity is a function of everything that has energy (see the stress energy tensor). It’s a very unusual “force” in this regard. This leads to interesting situations like a perfectly mirrored box of light (if you could have such a thing) weighing more on a scale than a box without light in it. Also, a spinning cue ball or a compressed spring weigh more than a stationary ball and an uncompressed spring. Granted, these differences are so small as to be undetectable by any equipment we could ever build, but it’s still interesting to think about.
- saagarjha 6y agoYou're right, I'm being stupid. Thanks for pointing that out!
- beamatronic 6y agoDo materials weigh less when cooled to absolute zero?
- JProthero 6y agoThe weight of a sample of matter depends on its total mass energy, and heat contributes to that total. If matter is cooled, it will weigh less, and vice-versa; if it is heated it will weigh more. At the kinds of temperatures that normally exist on Earth, the thermal contribution to the total mass energy of a sample of matter is trivial, but in extremely hot conditions, like the first fractions of a second after the big bang, the situation is reversed.