4 ms·
> A 30,000 ton ore train in Brazil will take about that long to stop, due to the nature of that weight strung out over 2.5 miles of distance. I once learned in
by ythn 8y ago
> A 30,000 ton ore train in Brazil will take about that long to stop, due to the nature of that weight strung out over 2.5 miles of distance.
I once learned in a physics class that weight has nothing to do with the stopping distance, but rather the steel on steel friction coefficient.
- LoSboccacc 8y agoWeight and ground pressure cancel each other out in the friction equation. The issue is where all that heat goes. Heated brakes will fade, glaze, fail, break, burn or a combination of the above, so there are limits on how much braking force you can apply to wheels
- marvin 8y agoThere are lots of assumptions in that entry-level physics exercise, for instance that all the energy can be dissipated without destroying anything (that the brakes are able to utilize the full friction available) and also that the entire weight of the vehicle rests on top of the wheels performing the braking.
- kposehn 8y agoExcellent point - it’s the rolling resistance indeed. I pointed out the size for reference (easier than saying 480,000 lbs rolling resistance :)