Blacksheep, Hmmmm....sorry physics doesn't work like that. Mass doesn't double. Whether you hit a tree or a skier at the same speed from the opposite direction the impact to you will be the same ( assuming you and the other are of equal weight).
Probably not the time to be pedantic but this is exactly how physics works, speed is relative, the skiers speed relative to the earth is irrelevant, it is their speed relative to each other that counts, if they are both travelling in the same direction but one at 20mph and the other at 100mph and they collide, the impact speed is 80mph same if one is stationary and one is doing 80 or if they are both doing 40 in opposite directions
Obviously A snowHead isn't a real person
Obviously A snowHead isn't a real person
Sigh.... You have not taken mass into the equation.
I'll state it one more time, 2 skiers coming towards each other at 40mph and impacting into each other is no different to each of those skiers going into a wall at 40mph. I.e, they both come to an instant stop from 40 >0. The 80mph in this scenario is just a red herring. It is not the same as say one skier hitting a stationary object at 80mph, the injury would be far greater upon that person.
The original poster stated "you can get an 80mph head on collision...." which is wrong, you don't just add up the speeds, you look at the de-acceleration. Each person's mass is deaccelerating from 40mph > 0.
Well, the person's real but it's just a made up name, see?
Well, the person's real but it's just a made up name, see?
@king key, Sorry, your argument is just wrong. If you were right then one skier standing still being hit by another doing 40mph the stationary skier would feel nothing.
What is your imaginary wall made out of. 6' thick brick wall and then, no the speed of the other skier is pretty much irrelevant. Make the wall out of paper and it isn't.
Sigh.... You have not taken mass into the equation.
I'll state it one more time, 2 skiers coming towards each other at 40mph and impacting into each other is no different to each of those skiers going into a wall at 40mph. I.e, they both come to an instant stop from 40 >0. The 80mph in this scenario is just a red herring. It is not the same as say one skier hitting a stationary object at 80mph, the injury would be far greater upon that person.
The original poster stated "you can get an 80mph head on collision...." which is wrong, you don't just add up the speeds, you look at the de-acceleration. Each person's mass is deaccelerating from 40mph > 0.
This is only the case if the two skiers are identical weights. Let's assume one is the owner of a Bavarian brewery and the other is Zola Budd....
The collision is only 'non elastic' to a point.
Anyway, snowHeads is much more fun if you do.
Anyway, snowHeads is much more fun if you do.
But:
The better comparison to draw is if a skier travelling at 40mph hits a stationery skier, in which case the stationery skier would absorb some of the impact of the collision and deflect away from the point of impact. So if both skiers were of the same mass then the collision would be equivalent to each skier going into a solid object at 20mph.
So then if each is doing 40mph in a head on then the accident becomes twice as serious, which is the point the poster was trying to make I think.
All it takes is two skiers doing wide turns 180 degrees out of phase with each other and sooner or later they come together as one traverses left and the other to the right.
If two skiers are doing wide turns on a piste they should both be pretty aware of each other and so no need for an accident at all, let alone said accident being inevitable.
The above being said I am one of those who believe sometime stuff does just happen, and not every accident has to be someones fault/negligence.
Then you can post your own questions or snow reports...
Then you can post your own questions or snow reports...
chaletgirl wrote:
I know it is generally the person behind's fault if they hit someone lower down but in January, I had a boarder decide to turn left across a very narrow bit of piste. He had his back to the piste when on my right and just decided to go to the left side without looking over his shoulder or making any kind of safety check. I had no where to go and ended up hitting him with a ski either side of his body and we both fell. He seemed ok and I had two badly twisted knees (luckily no real damage but just adding to the problems they already have)... I am now ridiculously nervous of other skiers/boarders. Its taken all my confidence away and I've barely skied this season due to it being busy and me being massively nervous about my knees and other people
Part of the ski lesson should be about etiquette on the piste. There should be more about speed, courtesy, distance etc visible in resorts (at lift queues?) to remind people.
It is a dangerous sport that can be mostly safe with care. But it needs all partakers to have more care........
Close quarters situations can happen very quickly, even on an empty piste. This 30 second video show me having a near collision with another snowboarder, if the piste is quiet I will make wide S carves which leaves me crossing the piste fairly fast. In hindsight I should have cut short that turn when I first saw the other guy, but even reacting as soon as I saw him start to turn towards me was only just enough. I don't think he is aware of me until we are less than a metre apart even though I can "see his nose" a couple of seconds earlier.
@king key, Sorry, your argument is just wrong. If you were right then one skier standing still being hit by another doing 40mph the stationary skier would feel nothing.
What is your imaginary wall made out of. 6' thick brick wall and then, no the speed of the other skier is pretty much irrelevant. Make the wall out of paper and it isn't.
You're joking right?
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@king key, would you rather walk into a stationary car or walk into a car coming at you doing 40mph? They are not the same.
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Ski the Net with snowHeads
It is more to do with velocity than speed
snowHeads are a friendly bunch.
snowHeads are a friendly bunch.
but...does the plane take off from the treadmill?
And love to help out and answer questions and of course, read each other's snow reports.
And love to help out and answer questions and of course, read each other's snow reports.
dode wrote:
@king key, would you rather walk into a stationary car or walk into a car coming at you doing 40mph? They are not the same.
You are completely missing out the physics of the scenario and of mass (assumed equal) coming in opposite directions. I'll correct your statement to try and make it better fit the scenario.
"would you rather run at 40mph into a stationary car or be stationary and be struck by a car coming at you doing 40mph?"
The result would be similar (except the car carries more mass so would cause more damage).
Last edited by And love to help out and answer questions and of course, read each other's snow reports. on Wed 15-03-17 15:39; edited 1 time in total
So if you're just off somewhere snowy come back and post a snow report of your own and we'll all love you very much
So if you're just off somewhere snowy come back and post a snow report of your own and we'll all love you very much
It's not to do with velocity but with conservation of momentum.
I would always position myself on the left hand side of the narrow piste, to maximise my view of people in close proximity.
I do exactly the same. It's one of those things you learn from experience, but is good advice to anyone who would listen. It's a case of riding 'defensively'. I do similar when out on the bike, if i am riding 'middle of the lane' rather than tucked into the edge, it doesn't imply i am hogging the road - it implies I am aware the road is in poor potholed condition, and I am trying to avoid them or a dangerous evasive manoeuvre.
@chaletgirl, sorry to hear you had a tumble. A nervousness / suspicion of other slope users is a healthy thing and it's a shame if it is putting you off - I hope you can recover some confidence!. You haven't indicated if this was a narrow 'cat track' or a steeper run. If a cat track ( and apologies if this is already clear to you) bear in mind that these are 'awful' things for boarders... sketchy, icy, no defined slope or edge to ride on, and you should be ready to anticipate that a boarder may go 'crazy ivan' at any point.
It was a point where the piste narrows for a rope pull.
I did a number of things wrong but, whilst I accept it was my fault, I STILL maintain that people (boarders and skiers) should look before they 'pull out'!!
I have done some boarding, not as much as skiing (although that might have to change next season) and I used to ski with boarders a lot. So I'm not totally oblivious to the issues.
I wasn't looking to blame, just comment on how people behave on the piste. We both made errors but the fault was mine
As a biker in the summer (well, all year round if I bring my bike out here), I am used to anticipating what other people are going to do and taking avoiding action. A lot of the issue of this incident was the fact that I really hadn't skied much and was out with people faster than me so was concentrating as much on where they were going (NOT trying to keep up) as on everyone around me. Like I said, I did a number of things wrong. But one thing I will never do is just pull out into a piste without checking who is behind me. On a board or on skis!!
BoardieK wrote:
chaletgirl wrote:
I know it is generally the person behind's fault if they hit someone lower down but in January, I had a boarder decide to turn left across a very narrow bit of piste. He had his back to the piste when on my right and just decided to go to the left side without looking over his shoulder or making any kind of safety check. I had no where to go and ended up hitting him with a ski either side of his body and we both fell. He seemed ok and I had two badly twisted knees (luckily no real damage but just adding to the problems they already have)... I am now ridiculously nervous of other skiers/boarders. Its taken all my confidence away and I've barely skied this season due to it being busy and me being massively nervous about my knees and other people
Part of the ski lesson should be about etiquette on the piste. There should be more about speed, courtesy, distance etc visible in resorts (at lift queues?) to remind people.
It is a dangerous sport that can be mostly safe with care. But it needs all partakers to have more care........
Close quarters situations can happen very quickly, even on an empty piste. This 30 second video show me having a near collision with another snowboarder, if the piste is quiet I will make wide S carves which leaves me crossing the piste fairly fast. In hindsight I should have cut short that turn when I first saw the other guy, but even reacting as soon as I saw him start to turn towards me was only just enough. I don't think he is aware of me until we are less than a metre apart even though I can "see his nose" a couple of seconds earlier.
Yup - when I had more confidence, I found I was much more able to make quick changes and this was the first time I have ever crashed into anyone in nearly five seasons. People don't look around. But, because I'm used to having to be aware of everything when on two wheels, I generally transfer that to skiing. So have been beating myself up about the crash since January - probably another reason I've not got my confidence back, cos I'm not convinced of my abilities any more and am ridiculously wary of other people to the point that when I went out yesterday, I really didn't enjoy myself. I'm sure I'll get it back, but I'm not good on slush anyway, so I'll start again next season!!
Otherwise you'll just go on seeing the one name:
Otherwise you'll just go on seeing the one name:
BoardieK wrote:
It's not to do with velocity but with conservation of momentum.
I am one of those who believe sometime stuff does just happen, and not every accident has to be someones fault/negligence
As am I - but increasingly seems to be a minority view these days, someone must be to blame
Obviously A snowHead isn't a real person
Obviously A snowHead isn't a real person
Boris wrote:
Quote:
I am one of those who believe sometime stuff does just happen, and not every accident has to be someones fault/negligence
As am I - but increasingly seems to be a minority view these days, someone must be to blame
When it comes to collision accidents of most sorts (road, snow, water) though there are codes of conduct or rules of the road so in the great majority of cases there is blame for not following them. Yes crap happens when a binding explodes spontaneously or even a hidden patch if ice is exoosed but your common or garden "I couldn't avoid him guv!" or "I didn't see her" will usually have a clear cause and effect. The "chill out it was an accident" attitude in skiing is the one which enables clowns to get up to the sort of speeds without skill that do result in fatalities.
Well, the person's real but it's just a made up name, see?
Well, the person's real but it's just a made up name, see?
My sister got taken out when we were skiing the other day. We were skiing down a short blue run before the run forked into a blue and black. On the slope just above the fork there were quite a few people. We all stick to the left and 3 of us pull up at the side just at the fork. We all turn around hearing a yelp and see skis and poles lying all over the slope, my sister in the snow and a guy rolling down the slope. He picks himself up, asks if she's ok (she was fine) and then skis off. Apparently he just skied straight into the back off her, no word of apology or anything.
I should note we are slightly doubtful she was completely blameless given she took one of us out on the border cross earlier but still seemed pretty poor from the bloke not to even offer an apology.
Some interesting physics above.....and some hilarious.
The important bit of that vid is that the total momentum after the collision is the same as the total momentum before the collision. If one skier is standing still he has no monentum. When someone tits him at 40 MPH they will probably come out with half the momentum of the moving skiier. If they are both moving at 40MPH then there is twice as much momentum in the system, flesh and bone will need to absorb twice as much energy than if one was standing still
I am probably hitting 40mph traversing across the piste, give someone doing the
same but out of phase and you can get an 80mph head on collision. .
Nope, it doesn't work line that, the 2 speeds don't double to give a higher impact. Imagine you skied at 40mph into a brickwall........and at the same time the other skier also skied into the same wall from the opposite direction. You both hit the the wall at 40 mph and no higher, you cause the same damage as though you skied into each other. (i.e not combined to make an 80mph crash), I hope this makes sense and I do not recommend skiing into brickwalls.
I see what you are trying to say but another skier is not a brick wall, just as the space video demonstrates, if you hit a stationary skier at 40 mph, then some of the impact energy will cause the other skier to move and the rest will be absorbed by crumpling bodies, hitting a skier of similar mass in a head on collision, both skiers will stop dead and all of the energy from both skiers will be absorbed by crumpling bodies , perhaps some rebound
Then you can post your own questions or snow reports...
Then you can post your own questions or snow reports...
Bottom line is that two of us went out to enjoy ourselves and one of them made a tragic mistake
After all it is free
After all it is free
tangowaggon wrote:
king key wrote:
tangowaggon wrote:
I am probably hitting 40mph traversing across the piste, give someone doing the
same but out of phase and you can get an 80mph head on collision. .
Nope, it doesn't work line that, the 2 speeds don't double to give a higher impact. Imagine you skied at 40mph into a brickwall........and at the same time the other skier also skied into the same wall from the opposite direction. You both hit the the wall at 40 mph and no higher, you cause the same damage as though you skied into each other. (i.e not combined to make an 80mph crash), I hope this makes sense and I do not recommend skiing into brickwalls.
I see what you are trying to say but another skier is not a brick wall, just as the space video demonstrates, if you hit a stationary skier at 40 mph, then some of the impact energy will cause the other skier to move *absolutely, but the discussion was about to 2 skiers approaching each other which is a different story and the rest will be absorbed by crumpling bodies, hitting a skier of similar mass in a head on collision, both skiers will stop dead and all of the energy from both skiers will be absorbed by crumpling bodies *indeed, exactly the same as going into a brick wall which I have tried to point out, perhaps some rebound
All I was trying to point out was that 2 skiers going into each other whilst both travelling at 40mph is not the same as an 80mph collision. I don't want to start a fight it's just a physics principle.
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You'll get to see more forums and be part of the best ski club on the net.
As a physics teacher, some of the physics on here is quite interesting. Kinetic energy is actually equal to velocity squared so if you double your velocity you quadruple your stopping distance and the amount to f energy you have, should you slam in to them. That said, ski collisions and falls are so complex, with so many factors that it's hard to model mathematically. Helmets another impact absorbers reduce force and therefore injury.
I have seen a few major changes since I started 30 years ago:
Lift systems have massively improved meaning far more people are skiing the mountains rather than queuing. The pistes are busier.
The season is shorter and the highest resorts are much busier when snow is sparse.vt at new year 2016 was unbelievable, so I'm told.
Far more people wear helmets
Carved skis mean a far greater percentage of skiers are more in control.
Piste maintainance is so much better. People are far more in control than on the old yesteryear mogulled stuff but they also travel much quicker and are not traversing as much.
Instruction is sooo much better and people learn better technique and much quicker these days.
There are far less boarders than there used to be
There are far more people doing tricks, jumps and skiing backwards on the mountains these days.
People seem far angrier when crashed in to these days. Being taken out like a skittle was all part of the fun of it back in the day.
Knees haven't really improved in the past thirty years and still aren't really fit for purpose.
For a place with lots of people sliding about at reasonably high speeds, alcohol is readily consumed.
Trees are as hard as the always were.
A sunburnt 60 mph snow plough skier nearly taking your head off as they fly by 6 feet in the air is almost always British.
Ski the Net with snowHeads
Ski the Net with snowHeads
king key wrote:
All I was trying to point out was that 2 skiers going into each other whilst both travelling at 40mph is not the same as an 80mph collision. I don't want to start a fight it's just a physics principle.
Show us using equations. I like equations
snowHeads are a friendly bunch.
snowHeads are a friendly bunch.
cameronphillips2000 wrote:
Knees haven't really improved in the past thirty years and still aren't really fit for purpose.
I love this. Well, all of the post, but I really love this bit!!
And love to help out and answer questions and of course, read each other's snow reports.
And love to help out and answer questions and of course, read each other's snow reports.
Thornyhill wrote:
king key wrote:
All I was trying to point out was that 2 skiers going into each other whilst both travelling at 40mph is not the same as an 80mph collision. I don't want to start a fight it's just a physics principle.
Show us using equations. I like equations
+ 40mph = = + 40mph
Best I could do at short notice.
So if you're just off somewhere snowy come back and post a snow report of your own and we'll all love you very much
So if you're just off somewhere snowy come back and post a snow report of your own and we'll all love you very much
@king key, Will that be a no then? I was hoping you would demonstrate using momentum and relativistic kinetic energy rather than a cartoon.
What is the closing speed of two skiers moving towards each other if they are both travelling at 40MPH?
You know it makes sense.
You know it makes sense.
Sigh..... humour wasted.
The closing speed is obviously 80mph, but that was never in question was it.
Otherwise you'll just go on seeing the one name:
Otherwise you'll just go on seeing the one name:
@cameronphillips2000, "Carved skis mean a far greater percentage of skiers are more in control"
No. Not at all. They think they are in control. They are not. But they are carrying more speed.
Poster: A snowHead
Poster: A snowHead
@king key, what is the closing speed of one skiier moving at 80 towards one standing still?
80 again. Right?
So from the frame of reference of one skiier in either scenario the other skiier is approaching them at 80 MPH.
Now if the skiier who is standing still is replaced by a brick wall or a tree, the system will have exactly the same momentum and kinetic energy as two skiers hitting each other at 40MPH. It is a principle of physics. HTH
Obviously A snowHead isn't a real person
Obviously A snowHead isn't a real person
Perhaps out of respect for the dead and the injured we should move the physics discussion (and the cartoons) to a different thread? Maybe continue in après?
Well, the person's real but it's just a made up name, see?
Well, the person's real but it's just a made up name, see?
Thornyhill, If you can't understand the difference between a single object travelling at 80mph and 2 objects travelling towards each other at 40mph each then there is really no point in going any further.
OK, I give up, if you believe the laws of physics operate differently in your world then that's just fine, enjoy them.
if you believe the laws of physics operate differently in your world then that's just fine, enjoy them.
Not fine, Einstein says so
Anyway, snowHeads is much more fun if you do.
Anyway, snowHeads is much more fun if you do.
In Ellmau last week some of the lift queues seemed to be the dangerous place.
Some folks carried their speed right to the back of the line while others slowed down before. As folks were naturally funnelled to the same spot it was too busy to be cutting through at speed.
In my experience while there are many skiers who ski down the piste at 40 mph I have not seen many capable of skiing up the piste at that speed so headon collisions are very unlikely
Then you can post your own questions or snow reports...
Then you can post your own questions or snow reports...
@Rabbie, so long as they all remember to only ever turn to the left
After all it is free
After all it is free
Rabbie wrote:
In my experience while there are many skiers who ski down the piste at 40 mph I have not seen many capable of skiing up the piste at that speed so headon collisions are very unlikely
it's when skiers are traversing across the piste that head on collisions are possible
You'll get to see more forums and be part of the best ski club on the net.
You'll get to see more forums and be part of the best ski club on the net.
All the physics is just too long ago for me now and totally unused since.
Sad news and not surprising to read the description of the location. I don't know it and have never been there but I'll bet we can all think of at least one similar junction/merge/split or whatever in the resorts we have been to that is just as bad and results in numerous accidents every winter.
Yes its great that resorts are spending ever more millions on new lifts and facilities to make things better but of those areas I refer to above how many of them could be vastly improved by spending just some of that on a topographical scientist and the hire of a few bulldozers one summer?
Ski the Net with snowHeads
Ski the Net with snowHeads
Just one comment on the use of speed when skiing. There are times when you need to carry speed, such as when coming back up a hill or there is a long flat stretch. Now I've seen times where people are not going appropriately fast enough in these situations and they can cause an issue, much as a car doing an inappropriate speed on a motorway would. It is of course still the responsibility of the person passing them to keep safe but hopefully you appreciate my point.
FAQ
Poster: A snowHead
I'm sure I'll get it back, but I'm not good on slush anyway, so I'll start again next season!!
