4 ms·
"The amount of pressure needed for a small sample is roughly the equivalent of someone dropping 10-lb hammer from a height of one meter, Qiao said." On Earth or
by endianswap 9y ago
"The amount of pressure needed for a small sample is roughly the equivalent of someone dropping 10-lb hammer from a height of one meter, Qiao said." On Earth or with Mars's gravity?
- dotancohen 9y agoAnd are those metric lbs or imperial meters? That sentence is quite the example of unit confusion!
- averagewall 9y agoI initially thought that too but realized it was a meaningless concern. Even if you knew g, it wouldn't help because the pressure also depends on the thickness of soil it's landing on, as well as its mechanical properties - like how much it's already been compressed. A hammer dropped onto concrete exerts more pressure than it does dropped onto sand. Also, what's the shape of the footprint of the hammer? Error in that will be more than the difference between Earth and Mars gravity.
- peterwwillis 9y agoSee comments below for the link to their paper in Nature. Most relevant test case is "Impact test, Flexible boundary condition", where they give all the data on their test methodology. If you load Supplementary Data, Figure S9[1], it shows 400MPa at 1ms. It also shows (for the above test) around 9mm displacement at what looks like 365MPa? I suck at math so I'll let someone else figure out the force. [1] https://static-content.springer.com/esm/art%3A10.1038%2Fs41598-017-01157-w/MediaObjects/41598_2017_1157_MOESM1_ESM.pdf https://static-content.springer.com/esm/art%3A10.1038%2Fs415...
- tyingq 9y agoWouldn't they just use a hand operated mechanical press though? Add hydraulics if you need more pressure. Something like this thing: https://www.youtube.com/watch?v=v7rgjxHP-yA https://www.youtube.com/watch?v=v7rgjxHP-yA with whatever adjustments for the mold and needed pressure.