4 ms·

That's almost 3Gs of acceleration. Impressive!

by btbuildem 3y ago

rob74 3y ago
Thanks! I was about to ask how many Gs this translates too, my physics are a bit rusty...
- mrb 3y ago
  In GNU units you can just do: $ units -t '100 kph / (.956s) / gravity' 2.9629132
  - world2vec 3y ago
    TIL!
  - rjmunro 3y ago
    That query works in Wolfram Alpha too: https://www.wolframalpha.com/input?i=100+kph+%2F+%28.956s%29+%2F+gravity https://www.wolframalpha.com/input?i=100+kph+%2F+%28.956s%29...
  - lucgommans 3y ago
    Rather than teaching a separate utility, I would recommend qalc which has unit conversions built in :) $ qalc -t 100km/h / 0.956s to gee 2.9629132 gees (where -t is for terse mode; by default it expands unit abbreviations and adds parentheses so you see whether it did what you wanted) The reason I recommend it is because it does so much more, I really love this utility since discovering it about a year ago. Example of using time notation combined with uncertainty and unit conversion: > (18:41 - 09:00+/-00:30) hours * 250 W to kWh (((1121 / 60) - (9±0.5)) * hour) * (250 * watt) = approx. (2.4208333±0.125) kW*h
    - chungy 3y ago
      The irony of advocating against a "separate utility", and then promoting a separate utility...
      - lucgommans 3y ago
        You never use a calculator?
        chungy 3y ago
        I use calculators plenty, but I neither have that one installed nor use it. On my PC, I use either grpn or units. More often, I pull out my HP 48G+.
        lucgommans 3y ago
        GRPN for anyone else who doesn't know it: http://lashwhip.com/grpn.html http://lashwhip.com/grpn.html What I meant to say is that, if one uses a featureful calculator like qalc, then you get unit conversion included without needing two separate utilities. Of course, if you've used a(n obscure) calculator for decades then it may be easier to learn to use a separate unit convertor instead
        chungy 3y ago
        I wouldn't exactly call the HP "obscure", but it does support unit calculations too. And "units" is more than plenty when I want infix operations.
        mrb 3y ago
        In my usage, GNU units appears to be more featureful than qalc. For example I noticed that qalc lacks many definitions that I often use, such as energy density (eg. "gasoline"), mass density (eg. "golddensity"), energy units (eg. "therm"), astronomy (eg. "earthradius", "solarmass"), etc. And GNU units works just fine as a calculator. So, from my viewpoint, qalc is the "separate utility" that I don't need ;-)
        deleted 3y ago
        [deleted]
nayuki 3y ago
I did the calculation manually from memory: 3.6 km/h = 1 m/s. 1 g = 9.8 m/s^2. So, 100 km/h = 27.8 m/s. 36 m/s in 0.956 s is an average acceleration of 29.1 m/s^2. Divide that by 9.8 m/s^2 to get 2.96 g.
cocoa19 3y ago
So the same as the Gravitron amusement ride popular in fairs
maerF0x0 3y ago
i used this calculator[1]. Looks like 3.5 . Just for fun... Now, if we use the forces that air pilots can sustain for 2 seconds we're looking at about 0.35 seconds is around the limit. and 0.3 seconds would create about 11Gs enough to kill you (all according to quick googles of numbers. If they can get a car to do 9Gs for 2 seconds we're looking at about 635Km/hr !!
- semi-extrinsic 3y ago
  11G is not lethal for the short durations you need for 0-100 (or even 0-200). A typical car crash at 20 mph is around 20 G deceleration. If you look at racing car crash data, one study reports 50 G as approximately the threshold for when you start to see frequent brain injuries. https://pubmed.ncbi.nlm.nih.gov/16531891/ https://pubmed.ncbi.nlm.nih.gov/16531891/
  - maerF0x0 3y ago
    Nice, thanks for providing data. As I said, all those numbers came from a quick google search

That's almost 3Gs of acceleration. Impressive!

rob74 3y ago

Thanks! I was about to ask how many Gs this translates too, my physics are a bit rusty...

mrb 3y ago
In GNU units you can just do: $ units -t '100 kph / (.956s) / gravity' 2.9629132
- world2vec 3y ago
  TIL!
- rjmunro 3y ago
  That query works in Wolfram Alpha too: https://www.wolframalpha.com/input?i=100+kph+%2F+%28.956s%29+%2F+gravity https://www.wolframalpha.com/input?i=100+kph+%2F+%28.956s%29...
- lucgommans 3y ago
  Rather than teaching a separate utility, I would recommend qalc which has unit conversions built in :) $ qalc -t 100km/h / 0.956s to gee 2.9629132 gees (where -t is for terse mode; by default it expands unit abbreviations and adds parentheses so you see whether it did what you wanted) The reason I recommend it is because it does so much more, I really love this utility since discovering it about a year ago. Example of using time notation combined with uncertainty and unit conversion: > (18:41 - 09:00+/-00:30) hours * 250 W to kWh (((1121 / 60) - (9±0.5)) * hour) * (250 * watt) = approx. (2.4208333±0.125) kW*h
  - chungy 3y ago
    The irony of advocating against a "separate utility", and then promoting a separate utility...
    - lucgommans 3y ago
      You never use a calculator?
      - chungy 3y ago
        I use calculators plenty, but I neither have that one installed nor use it. On my PC, I use either grpn or units. More often, I pull out my HP 48G+.
        lucgommans 3y ago
        GRPN for anyone else who doesn't know it: http://lashwhip.com/grpn.html http://lashwhip.com/grpn.html What I meant to say is that, if one uses a featureful calculator like qalc, then you get unit conversion included without needing two separate utilities. Of course, if you've used a(n obscure) calculator for decades then it may be easier to learn to use a separate unit convertor instead
        chungy 3y ago
        I wouldn't exactly call the HP "obscure", but it does support unit calculations too. And "units" is more than plenty when I want infix operations.
        mrb 3y ago
        In my usage, GNU units appears to be more featureful than qalc. For example I noticed that qalc lacks many definitions that I often use, such as energy density (eg. "gasoline"), mass density (eg. "golddensity"), energy units (eg. "therm"), astronomy (eg. "earthradius", "solarmass"), etc. And GNU units works just fine as a calculator. So, from my viewpoint, qalc is the "separate utility" that I don't need ;-)
      - deleted 3y ago
        [deleted]

nayuki 3y ago

I did the calculation manually from memory: 3.6 km/h = 1 m/s. 1 g = 9.8 m/s^2. So, 100 km/h = 27.8 m/s. 36 m/s in 0.956 s is an average acceleration of 29.1 m/s^2. Divide that by 9.8 m/s^2 to get 2.96 g.

cocoa19 3y ago

So the same as the Gravitron amusement ride popular in fairs

maerF0x0 3y ago

i used this calculator[1]. Looks like 3.5 . Just for fun... Now, if we use the forces that air pilots can sustain for 2 seconds we're looking at about 0.35 seconds is around the limit. and 0.3 seconds would create about 11Gs enough to kill you (all according to quick googles of numbers. If they can get a car to do 9Gs for 2 seconds we're looking at about 635Km/hr !!

semi-extrinsic 3y ago
11G is not lethal for the short durations you need for 0-100 (or even 0-200). A typical car crash at 20 mph is around 20 G deceleration. If you look at racing car crash data, one study reports 50 G as approximately the threshold for when you start to see frequent brain injuries. https://pubmed.ncbi.nlm.nih.gov/16531891/ https://pubmed.ncbi.nlm.nih.gov/16531891/
- maerF0x0 3y ago
  Nice, thanks for providing data. As I said, all those numbers came from a quick google search