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On 2023-06-21, Commander Kinsey <CK1@nospam.com> wrote:
On Wed, 10 May 2023 22:04:54 +0100, Carlos E.R. <robin_listas@es.invalid> wrote:
On 2023-05-10 22:31, Bob F wrote:
On 3/12/2023 7:43 PM, ð Mighty Wannabe â wrote:
rbowman wrote on 3/12/2023 10:05 PM:
On Mon, 13 Mar 2023 00:30:39 -0000, Commander Kinsey wrote:
On Thu, 02 Mar 2023 03:09:14 -0000, rbowman <bowman@montana.com> wrote:
On Wed, 01 Mar 2023 15:05:31 -0000, Commander Kinsey wrote:
Why were they never made of something more grippy than highly
polished
steel?
https://en.wikipedia.org/wiki/Mount_Washington_Cog_Railway
Should be used on all tracks, then perhaps trains could stop in the
distance my car is required to by law.
Do the math. A fully laden coal car weighs about 140 tons. I\'ve never
been
bored enough to count cars when I stopped at a crossing but there are a
lot of them. Let\'s say 30 for the sake of argument, 4200 tons plus the
weight of the engines. Let\'s say 4 at 200 tons each. So, roughly 5000
tons
traveling at 50 mph. That\'s quite a bit of kinetic energy to dump in
300\'.
I can hear snapping axles and see flying wheels.
The wheels and the rails are steel. A train can never have enough
friction to stop at a short distance. The brakes can lock all the
wheels but the train will still move forward due to inertia.
All that need is train wheels made of rubber as hard as steel.
If you do that, then those wheels will be very low friction and braking
will be as bad as with steel wheels.
You need something that is soft to increase the contact surface and
grip. You have to choose, one thing or the other. Can\'t have both.
Friction isn\'t just related to surface area, but also material.
Friction just isn\'t related to surface area, but instead material.
On 22/06/2023 08:11, The Natural Philosopher wrote:
Moving relative to what?
You are correct that all motion has to be relative to something. In this
case, the object\'s motion is relative to the observer. The momentum of
an object is its mass times its velocity. Inertia is the property of
matter that resists changes in motion. It is proportional to mass and
independent of velocity. So, a massy object has inertia whether it\'s
moving or not. It only has momentum if it\'s moving relative to an
observer ¹².
I hope that helps! Let me know if you have any other questions.
Source: Conversation with Bing, 22/06/2023
(1) Difference Between Momentum and Inertia - Collegedunia.
https://collegedunia.com/exams/difference-between-momentum-and-inertia-physics-articleid-3934.
(2) Difference Between Momentum and Inertia - Momentum vs Inertia -
BYJU\'S. https://byjus.com/physics/difference-between-momentum-and-inertia/.
(3) Difference Between Momentum and Inertia - Vedantu.
https://www.vedantu.com/physics/difference-between-momentum-and-inertia.
On 2023-06-22, The Natural Philosopher <tnp@invalid.invalid> wrote:
On 21/06/2023 19:45, Max Demian wrote:
On 21/06/2023 17:05, The Natural Philosopher wrote:
On 21/06/2023 10:14, jon wrote:
Momentum not Inertia.
Same thing
A massy object has inertia whether it\'s moving or not. It only has
momentum if it\'s moving.
Moving relative to what?
Moving relative to whatever.
Frame of reference.
On 17/07/2023 22:35, Commander Kinsey wrote:
On Sat, 10 Jun 2023 20:23:25 +0100, Dan Purgert <dan@djph.net> wrote:
On 2023-06-10, Commander Kinsey wrote:
[...]
We put grippy wheels on cars, we could put them on trains too.
Sure, get a \"grippy\" material that can hold >100 tons (>200,000 pounds)
in a single car with 4 (or even 6) axles, and maybe you have an idea.
Oh, and it has to have a service life of a quarter million miles
(minimum).
Ok, put steel wheels on cars.
They do. And they run them on rails. Several joined together.
On 17/07/2023 22:35, Commander Kinsey wrote:
On Sat, 10 Jun 2023 20:23:25 +0100, Dan Purgert <dan@djph.net> wrote:
On 2023-06-10, Commander Kinsey wrote:
[...]
We put grippy wheels on cars, we could put them on trains too.
Sure, get a \"grippy\" material that can hold >100 tons (>200,000 pounds)
in a single car with 4 (or even 6) axles, and maybe you have an idea.
Oh, and it has to have a service life of a quarter million miles
(minimum).
Ok, put steel wheels on cars.
They do. And they run them on rails. Several joined together.