The wheels on the bus go, 'Screech screech screech'

[ZedOmega]

Short one: got on bus to go follow job lead. Not even five seconds go by before the bus driver has to screech to a halt because of the idiot in the red car who didn't see him.

Idiot in the red car shouted through the window at the bus driver like he didn't know how to drive.

[Mytical]

Hehe, yes I think people have no concept of Physics. In order of how long it takes something to slowdown, stop, etc it is like this. Train > Semi > Bus > etc. ((Not counting planes and sea craft of course )). Would include Tanks, but they normally are going slow lol. Include MASS with speed and you really don't want to be on the wrong end of these things.

How some people do not see them (I think they do, but their brain is on vacation in Tahiti) is beyond me. Respect the MASS of a vehicle, you live longer .

[smileyeagle1021]

As mom used to say, it doesn't matter who has the right of way, if he's bigger than you, he'll survive the crash.

[mikoyan29]

Hehe, yes I think people have no concept of Physics. In order of how long it takes something to slowdown, stop, etc it is like this. Train > Semi > Bus > etc. ((Not counting planes and sea craft of course )). Would include Tanks, but they normally are going slow lol. Include MASS with speed and you really don't want to be on the wrong end of these things.

How some people do not see them (I think they do, but their brain is on vacation in Tahiti) is beyond me. Respect the MASS of a vehicle, you live longer .

That is why I don't run train tracks. Anything that can hit me where the driver of the vehicle wont even feel it is something I don't want to be in front of.

[Chromatix]

It's not entirely true that the driver wouldn't feel it. Let's do the maths from Newtonian Physics 101:

Train: assume only a 100-ton (100000kg) locomotive, moving at 40m/s (about 80mph). This is accurate for the immediate impact even if there's a freight train behind it, because the coupling must compress to bring that extra weight to bear.

Kinetic energy of train: 100000 * 40*40 = 160000000 = 160 MJ.

Car: assume a 2-ton model, stationary on the track. Kinetic energy of car: zero. Mass of car: 2000kg.

Kinetic energy of train+car after impact: 160 MJ, just as before.

Speed of train+car after impact: sqrt(160MJ / 102t) = 39.6 m/s.

The locomotive was slowed down by less than 1 mph. This is still enough to compress the coupling to the train behind it, so it will be pushed "back" by a few inches over the course of less than a second.

As far as the driver's concerned, he's suddenly now leaning a bit further forward in his seat. Easy for him to correct, but not quite the same as not feeling it.

Also, if the car has attached itself to the front (as I've assumed here), it will now be throwing dirt and/or ballast all over the place. This is likely to have a long-term braking effect.

[ZedOmega]

Is it odd that I understood all of that perfectly despite never having taking Physics in high school?

[greek_jester]

Also, if the car has attached itself to the front (as I've assumed here), it will now be throwing dirt and/or ballast all over the place. This is likely to have a long-term braking effect.

You know, my grin was getting bigger & bigger throughout this post. That last paragraph made me start giggling, though.

Younger sister: 'What's so funny?'
Me: 'A physics post about the effects of a train hitting a parked vehicle.'
Younger sister: Ooookay...

[Chromatix]

Ah, deadpan humour.

I think basic Newtonian mechanics is often covered in mathematics courses, since it represents one of the simplest forms of "applied maths". That may be why it looks familiar. Much of physics is just common sense, advanced algebra and/or calculus, and making sure your units match, anyway.