11
votes
Why does a plastic bag rip when it is raised to a higher position when being held but not when it is stationary?
This is like holding a weight $mg$ with a string which can break with a tension of $1.1 mg$. When you are not moving the bag, or moving it at a uniform speed, the string's tension is constant at $mg$,...
- 9,428
6
votes
Why does a plastic bag rip when it is raised to a higher position when being held but not when it is stationary?
You move the bag upwards with an acceleration. If you were to pull the bag up with infinitesimal acceleration, it would not rip then, because the force required for that would approach zero. But since ...
- 91
1
vote
Do there exist materials whose Opacity varies with temperature?
There are certainly materials which change colour with temperature. This behaviour is called thermochromism.
- 47.3k
1
vote
Refractive index of titanium dioxide films as a function of wavelength for 400 C ° annealed films
I am not sure which spectrophotometer you are using, but the data looks reasonable from my perspective.
I am not sure why you would get directly a measurement of the refractive index from the ...
- 510
1
vote
Materials known to have higher density than Osmium at at high pressure and/or low temperature
Osmium’s density at 500 Gpa is about 35~36 g/ml according to from dividing the room temp density by the percent volume
- 11
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