Jan and Klodi's Party Bus - part II **off topic discussion**

Lumen

tomasrojo wrote: »

They tested it, and the two scenarios did result in the same force being applied to the car hitting another car as the car hitting a wall.

I guess the knowledge is not really that useful unless you find yourself in the situation where you have the direct choice between hitting a wall and an oncoming car.

Who's in the car? What's behind the wall? Maybe toddlers, or old people, or Mexicans. Or Mexican old people carrying toddlers. Does the wall have insurance?

Life is so complicated.

tomasrojo

I was just prompted to remember it by the (totally reasonable) "combined impact" comment. And it's nicely counter-intuitive. I take your point about Mexicans et al.

I did have a friend who fell asleep at the wheel and hit a tree, and subsequently told everyone how lucky she'd been that she hadn't hit another car. She meant that she wouldn't have survived the head-on collision. I told her about Mythbusters. It wasn't helpful.

RayCun

tomasrojo wrote: »

I was intrigued by the episode of Mythbusters where they responded to a viewer's complaint that they'd assumed that a car hitting another car head on was worse than the car hitting a wall (or something like that). By Newton's Third Law of Motion, the two scenarios produce the same force on the first car (cars travelling at equal speed colliding head on, versus a single car hitting a stationary wall at the same speed).

what situations are you comparing? what is "the same speed"

You are in a car driving at 50km/h and you hit a wall, vs, you are in a car driving at 50 and hit a car that is also driving at 50 head-on.

in this case hitting the wall would seem the better choice

or

You are in a car driving at 100km/h and you hit a wall, vs, you are in a car driving at 50 and hit a car that is also driving at 50 head-on.

in this case, there are no good choices, but the crumple zone of the other car might help. A bit.

tomasrojo

RayCun wrote: »

what situations are you comparing? what is "the same speed"

Sorry, wasn't clear.

Two cars (A and both travelling at 50km/h in head-on collision produces the same force on A as a single car A travelling at 50km/h hitting a wall (provided the wall doesn't give).

I guess crumple zones might provide some give, which might make the head-on with B slightly more likely to result in a better outcome for the occupant of A.

RayCun

I guess the point is that if you hit another car head-on, although the total forces involved are greater, the damage that is done will be shared between your car and the other car.

But if you hit a wall (an ideal wall), it isn't damaged at all, all the damage is done to the car.

tomasrojo

RayCun wrote: »

I guess the point is that if you hit another car head-on, although the total forces involved are greater, the damage that is done will be shared between your car and the other car.

No, that's the mind-bending bit. The force is identical in both scenarios. Every action has an equal and opposite reaction. The wall, if it doesn't give, exerts a force on the car colliding with it that is equal to the force exerted by a 1.5 tonne vehicle travelling at 50km/h.

tomasrojo

The forces in both scenarios are exactly the same. What damage the forces do could be markedly different alright, as a car has a very different construction from a wall. I don't know how one does calculations or predictions around that.

But the basic insight from Newton's Third Law still applies: if the car doesn't knock over the wall, the wall stopped the car; that means the wall exerted a force equal to the force the car exerted, but in the opposite direction. Which is why the car stops.

Alek

But you are thinking of two identical cars hitting each other exactly head-on ("mirror collision") , which is very unlikely a real life scenario. If the other car has greater mass, or even lacks crumple zones, your car will receive greater damage. Same with the wall - is it solid block of concrete or a stack of loose bricks?

tomasrojo

If it's a stack of loose bricks, it won't stop the car dead, so the car will push through the wall, meaning that only some of the car's force has been matched. So that's a different scenario. Or, it might slow the car more gradually rather than forcing it to a very sudden stop, which means that the force isn't countered in one go.

Yeah, it's more of a thought experiment than something that happens very often, but one does intuitively think of the scenario with two cars as being more destructive, because of all the combined speeds and motion, but it's not necessarily the case. In particular, we don't think of the wall exerting a force, because it seems to be passive, but if it didn't exert an enormous force back on the car, the car wouldn't stop.

Alek

If it's a stack of loose bricks, it won't stop the car dead, so the car will push through the wall, meaning that only some of the car's force has been matched.

Same with a Hummer and a Micra, hey?

tomasrojo

Anyway, that was the episode:
http://mythresults.com/mythssion-control

Their explanation at the end is wrong though:
https://www.wired.com/2010/05/mythbusters-energy-explanation/

CramCycle

FFS
Someone in HR in work told Revenue I had left (I changed positions). Revenue then passed all my tax credits onto my partner and gave her a "carers credit".
So not only am I skint for the month, I will owe revenue money when they do sort it out as they gave me a credit that we are not entitled too.

robyntmorton

I'd argue that you didn't claim a carers credit, they mistakenly gave it to you. They messed up, not you (oh how I wish the system worked that way)

Hopefully you get it sorted out soon. We would save a fortune on red tape if only they thought through these things properly.

magicbastarder

ultimately, your tax affairs are your responsibility. your employer takes care of them for you as a gesture of goodwill.

at least, that's how i understand things; if your employer ****s up, it's legally up to you to hammer out the deal with revenue.

Hungrycol

CramCycle wrote: »

FFS
Someone in HR in work told Revenue I had left (I changed positions). Revenue then passed all my tax credits onto my partner and gave her a "carers credit".
So not only am I skint for the month, I will owe revenue money when they do sort it out as they gave me a credit that we are not entitled too.

Maybe its a new "restructuring" move. If you receive your P45 in the post there is no longer a requirement for your employment in the company.

CramCycle

I am not in trouble or anything, it is just annoying. No deal with Revenue to be made. They will just reclaim the credit in my P21 at the end of year. With other expenses etc. it will make negligible difference. It is just annoying. I expected X, I got X-Y, my partner got Z+Y +a little extra. At the end of the year, we will owe that little extra back, but it is a really tiny amount and medical bills over the year will cover it.

Hungrycol

CramCycle wrote: »

I am not in trouble or anything, it is just annoying. No deal with Revenue to be made. They will just reclaim the credit in my P21 at the end of year. With other expenses etc. it will make negligible difference. It is just annoying. I expected X, I got X-Y, my partner got Z+Y +a little extra. At the end of the year, we will owe that little extra back, but it is a really tiny amount and medical bills over the year will cover it.

Since it's the beginning of the tax year there is no reason why you have to wait for a P21 next year. They should be able to correct both of your tax certs and once they are on a cumulative tax basis it will correct itself in the your and her next pay run.

Rogue-Trooper

Rogue-Trooper wrote: »

Ok, there is something very wrong with my Edge 520. As above, yesterday morning it told me I did 2,227m on my commute in. On the way home it said I did 2,200m. This morning it claims I did 2,185m. The reality is in fact about 35m.

Why has it suddenly gone bat-sh1t crazy? Has the sea-level shifted in the last 48 hours and I didn't notice? I upgraded the software last week but the first couple of days were ok, it's only since yesterday. Any ideas oh wise ones?

Unknown Soldier wrote: »

Can you post a pic of it on your bike? From the side preferably.

Ok, tried a 'hard' reset (holding the power button for 10 seconds). It worked normally for one journey then went back to Mt Everest mode.

Tried a 'factory' reset last night, still the same issue this morning but also started telling me that it was 21 degrees celcius out instead of 7. All this because I updated the software.

Grrrrrrrrrrrr

On the plus side, it's giving me text & call alerts again which it wasn't doing for ages..........

Wishbone Ash

A close pass with a difference this afternoon in Rathgar - luxury saloon with the national flag of a South American country flying on the front corners.

Diplomatic immunity I suppose! :P

ford2600

Wishbone Ash wrote: »

A close pass with a difference this afternoon in Rathgar - luxury saloon with the national flag of a South American country flying on the front corners.

Diplomatic immunity I suppose! :P

Have a chat with these lads

https://youtu.be/kwC_IaY3BmY

TheBlaaMan

Rogue-Trooper wrote: »

Ok, tried a 'hard' reset (holding the power button for 10 seconds). It worked normally for one journey then went back to Mt Everest mode.

Tried a 'factory' reset last night, still the same issue this morning but also started telling me that it was 21 degrees celcius out instead of 7. All this because I updated the software.

Grrrrrrrrrrrr

On the plus side, it's giving me text & call alerts again which it wasn't doing for ages..........

There is a calibration check that my 520 asks me to do occasionally. Might be worth getting....

Unknown Soldier

Rogue-Trooper wrote: »

Ok, tried a 'hard' reset (holding the power button for 10 seconds). It worked normally for one journey then went back to Mt Everest mode.

Tried a 'factory' reset last night, still the same issue this morning but also started telling me that it was 21 degrees celcius out instead of 7. All this because I updated the software.

Grrrrrrrrrrrr

On the plus side, it's giving me text & call alerts again which it wasn't doing for ages..........

Try ditching the willie warmer and then set it horizontal on the bars, see if that helps.

I know someone who keeps getting twice the climbing meters that everyone else does on spins with him, and his garmin is at a similar angle.

None of the above might work though, and you might have a unit with a faulty barometer! (which takes its readings from a small hole on the back)

Right... I have to man up and get on the bike... but I am sooo tired

magicbastarder

Unknown Soldier wrote: »

None of the above might work though, and you might have a unit with a faulty barometer! (which takes its readings from a small hole on the back)

is it possible that the hole is blocked by the cover?

Alek

1. hole may be blocked by the cover
2. hole may be blocked by water trapped under the cover

CramCycle

Long story short, don't cover your hole when out riding.
Or
Protective sheaths are important but wait until everything is ready to go before putting one on.

magicbastarder

using an excessively thick sheath may result in reduced performance, and a lack of sensory input.

wanderer 22

Some Argy Bargy on the Dubai tour - https://www.theguardian.com/sport/2017/feb/02/andriy-grivko-dubai-tour-marcel-kittel-cycling?CMP=twt_gu

jpg images

robyntmorton

I know during live coverage it was said that Kittel, and others, made much of protesting to the commisaires about this. It wasn't seen in the live feed, but there was talk of an elbow to the head, and I see Eurosport have just tweeted that it may have been a punch. There's really no need at all for that.

https://twitter.com/Eurosport_UK/status/827159207363346433

Chuchote

Wearing the right clothes is important to cyclists

Doctor Bob

Chuchote wrote: »

Wearing the right clothes is important to cyclists

Agreed. I wouldn't be seen dead without my perfect Large Tibet Fur Muff.