Bizarre coincidence, but saved by their helmets.

On Thu, 30 Sep 2010 23:13:43 +0100, The Medway Handyman wrote:

Peter Keller wrote:
On Tue, 28 Sep 2010 18:04:06 +0100, The Medway Handyman wrote:



I wouldn't insult idiotic pathetic little ****s by comparing them to
you.

Oh the compliments are really flowing thick and fast aren't they
sweetie? I love you too.
I cannot wait for more!

*smooch*

Care in the Community obviously not working is it?


Ah and thank you for your kind concern about my wellbeing.
With your help I will attain the honour of pathetic despicable turd-
eating **** for brains ****wit in no time!


--
67.4 percent of statistics are made up.

The Medway Handyman said in

Paul - xxx wrote:
The Medway Handyman wrote:
Paul - xxx wrote:
The Medway Handyman wrote:
Mrcheerful wrote:
two more flying over the handlebars, I thought that never
happened to true cyclists? One of them clearly travelling too
fast for his abilities/the road.

Cyclists never land on their heads. Tony Raving has clearly
stated that the human body is specifically designed not to.

When? Do you have a link? I don't recall anyone saying that.

Oh but he did. Shortly after the **** claimed that helmets caused
strokes.
CBA to look it up.

"Cyclists never land on their heads" is totally different from "the
human body is specifically designed not to". I don't believe anyone,
except you, amongst others, has ever claimed cyclists never land on
their heads ...

You are confusing me with someone who cares what you think.

LOL, you care enough to make numerous replies.

--
Paul - xxx

'96/'97 Landrover Discovery 300 Tdi
Dyna Tech Cro-Mo comp

On Sep 29, 4:43*pm, Marc wrote:
On 29/09/2010 11:00, Derek C wrote:



On Sep 28, 8:45 pm, Tony *wrote:
Derek C wrote:

So if you have an accident where you have a head impact in the range
700 - 800 joules, up to 1100 joules in some cases, wearing a cycle
helmet will prevent a skull fracture.

Unlikely. *At those energies the helmet is receiving up to ten times its
maximum design energy and will fail catastrophically. *Second, at the
velocities associated with those energies, the additional mass of the
helmet strapped to the head adds about as much energy to the impact as
it absorbs if it works perfectly.

However the brain is most likely
to be damaged by a high g deceleration, whether or not the skull is
fractured, with a maximum short term tolerance of about 300 g for an
average person. Modern cycle helmets cushion the head so that they
limit the loading to about 200g in a reasonably survivable impact.

You know even less about neurology than you do about physics.
Coup-contrecoup injuries are not typically the problem.

Tony

You obviously haven't read the link I provided for Mark.

http://www.motorcyclistonline.com/ge...lmet_review/in...

I did, when I asked"
* However the brain is most likely
* to be damaged by a high g deceleration, whether or not the skull is
* fractured, with a maximum short term tolerance of about 300 g for an
* average person.

*Source?"

I expected a more rigorous source than a magazine article. You haven't
yet supplied your vector force diagram of a cyclist coming off "head
first" yet either , or even commented upon the physics of 100J equating
to a 10mph accident . Are you equipped to continue this discussion in
terms of physics, or as your critics point out is your contribution
simply to be arm waving and "commonsense"?- Hide quoted text -

- Show quoted text -

TRL PPR446 comes to more or less the same conclusions if you want
something more scientific. If you fall off a push bike or motorbike
and strike your head on the road surface, it matters little if you are
doing 5mph or 100mph, apart from subsequent minor abrasion injuries.
It's the height of the fall that is most significant, hence drop tests
are valid.

I can't find a Google reference to how many Joules a helmet will
absorb, as most papers refer to reducing g loadings. Even if it is
100J, the important thing is that it is the initial 100J and
subsequent loadings on the brain will be reduced by this amount, even
if the helmet fails at this stage.

If you apply the front brake hard at speed, the front wheel will act
as a fulcrum about which the whole bike and rider will rotate
(assuming the front tyre doesn't skid). Motorcyclists and BMX riders
make use of this effect to do stoppies, where the bike ends up
balanced on the front wheel (if you get it right!). See:

http://www.youtube.com/watch?v=KlLjF...xt=1& index=1

Derek C

On 02/10/2010 08:40, Derek C wrote:
On Sep 29, 4:43 pm, wrote:
On 29/09/2010 11:00, Derek C wrote:



On Sep 28, 8:45 pm, Tony wrote:
Derek C wrote:

So if you have an accident where you have a head impact in the range
700 - 800 joules, up to 1100 joules in some cases, wearing a cycle
helmet will prevent a skull fracture.

Unlikely. At those energies the helmet is receiving up to ten times its
maximum design energy and will fail catastrophically. Second, at the
velocities associated with those energies, the additional mass of the
helmet strapped to the head adds about as much energy to the impact as
it absorbs if it works perfectly.

However the brain is most likely
to be damaged by a high g deceleration, whether or not the skull is
fractured, with a maximum short term tolerance of about 300 g for an
average person. Modern cycle helmets cushion the head so that they
limit the loading to about 200g in a reasonably survivable impact.

You know even less about neurology than you do about physics.
Coup-contrecoup injuries are not typically the problem.

Tony

You obviously haven't read the link I provided for Mark.

http://www.motorcyclistonline.com/ge...lmet_review/in...

I did, when I asked"
However the brain is most likely
to be damaged by a high g deceleration, whether or not the skull is
fractured, with a maximum short term tolerance of about 300 g for an
average person.

Source?"

I expected a more rigorous source than a magazine article. You haven't
yet supplied your vector force diagram of a cyclist coming off "head
first" yet either , or even commented upon the physics of 100J equating
to a 10mph accident . Are you equipped to continue this discussion in
terms of physics, or as your critics point out is your contribution
simply to be arm waving and "commonsense"?- Hide quoted text -

- Show quoted text -

TRL PPR446 comes to more or less the same conclusions if you want
something more scientific. If you fall off a push bike or motorbike
and strike your head on the road surface, it matters little if you are
doing 5mph or 100mph, apart from subsequent minor abrasion injuries.
Are you really trying to say that a helmet will have the same effect
if the 80Kg rider has 197J of Ke or 79000J ?

It's the height of the fall that is most significant, hence drop tests
are valid.

Is your physics up to giving figures for a 1.75M fall under 1G at 5mph
compered with a 1.75M fall at 100mph?

I can't find a Google reference to how many Joules a helmet will
absorb, as most papers refer to reducing g loadings.

"Most papers", are you sure? What papers have you read?

Even if it is
100J, the important thing is that it is the initial 100J and
subsequent loadings on the brain will be reduced by this amount, even
if the helmet fails at this stage.

Really? so what happens if there is a 5mph blow to the head of a
stationary helmet wearer, does this mean that the "loading on the brain"
( forgetting the head's built in "shock absorbers") will be -87? How low
or high must the figure be to avoid brain damage?


If you apply the front brake hard at speed, the front wheel will act
as a fulcrum about which the whole bike and rider will rotate
(assuming the front tyre doesn't skid). Motorcyclists and BMX riders
make use of this effect to do stoppies, where the bike ends up
balanced on the front wheel (if you get it right!). See:

http://www.youtube.com/watch?v=KlLjF...xt=1& index=1

But where's the force vector diagram showing the rider coming off "head
first"? You are capable of producing one , aren't you? You wanted to use
physics to make your argument, I've yet to see you use any, do you
understand the principles and forces involved or do you simply cut and
paste words that you think will impress?

On Sat, 02 Oct 2010 10:32:45 +0100, Marc wrote:

If you apply the front brake hard at speed, the front wheel will act
as a fulcrum about which the whole bike and rider will rotate
(assuming the front tyre doesn't skid). Motorcyclists and BMX riders
make use of this effect to do stoppies, where the bike ends up
balanced on the front wheel (if you get it right!). See:

http://www.youtube.com/watch?v=KlLjF...xt=1& index=1

But where's the force vector diagram showing the rider coming off "head
first"? You are capable of producing one , aren't you? You wanted to use
physics to make your argument, I've yet to see you use any, do you
understand the principles and forces involved or do you simply cut and
paste words that you think will impress?

There is a process which kicks in before the rider's head is driven
into the ground, this process is informally known as "falling off" and
accounts for the fact that the most common serious injury in cycle
crashes appears to be broken collarbones.

Guy
--
http://www.chapmancentral.co.uk/
The usenet price promise: all opinions offered in newsgroups are guaranteed
to be worth the price paid.

On 02/10/2010 08:40, Derek C wrote:


I can't find a Google reference to how many Joules a helmet will
absorb, as most papers refer to reducing g loadings.


It seems you haven't even read TRL PPR446 otherwise you wouldn't have
needed to Google.


Your really are an empty vessel aren't you? You have no idea of the
physics involved, you don't grasp the concepts, you don't have any
resources apart from google and wikepedia, you can't even translate
acceleration using SI units and an agreed mass into Joules. I don't
think you have the capacity or knowledge to create a force vector
diagram and I have a feeling you had to use wikepedia to look up what I
was asking for, in short you sir are a fraud. You pepper your armwaving
with scientific sounding psuedobabble but you have nothing to back it up
with, your "common sense " is nothing but a pompous emperor walking
naked down the high street.

Derek C wrote:

TRL PPR446 comes to more or less the same conclusions if you want
something more scientific.

You mean the only thing on helmets you have ever read that says we don't
know the answer so we made one up? That would accord with your style of
science

If you fall off a push bike or motorbike
and strike your head on the road surface, it matters little if you
are doing 5mph or 100mph, apart from subsequent minor abrasion
injuries. It's the height of the fall that is most significant, hence
drop tests are valid.

Not, if as you are, you are postulating rotational couples that change
the directions of the velocity vectors.


I can't find a Google reference to how many Joules a helmet will
absorb, as most papers refer to reducing g loadings. Even if it is
100J, the important thing is that it is the initial 100J and
subsequent loadings on the brain will be reduced by this amount, even
if the helmet fails at this stage.

Except that the helmet has its own kinetic or potential energy it adds
into the equation.


If you apply the front brake hard at speed, the front wheel will act
as a fulcrum about which the whole bike and rider will rotate
(assuming the front tyre doesn't skid). Motorcyclists and BMX riders
make use of this effect to do stoppies, where the bike ends up
balanced on the front wheel (if you get it right!). See:


Again your own quaint take on physics. Lets have a look at what really
happens
http://www.youtube.com/watch?v=vc4WNCwnnJI&NR=1

Tony

Marc wrote:
you can't even translate
acceleration using SI units and an agreed mass into Joules.

Derek did try that here once but got it very badly wrong (used the
formula for momentum instead of kinetic energy) and protested vigorously
at length that he was right and everyone else wrong. So its no surprise
he's not willing to try that one again in public.

He does claim to be an atomic spectroscopist but quite how he manages to
be that without even a basic understanding of physics and energy is a
mystery.


Tony

On Oct 2, 10:32*am, Marc wrote:
On 02/10/2010 08:40, Derek C wrote:



On Sep 29, 4:43 pm, *wrote:
On 29/09/2010 11:00, Derek C wrote:

On Sep 28, 8:45 pm, Tony * *wrote:
Derek C wrote:

So if you have an accident where you have a head impact in the range
700 - 800 joules, up to 1100 joules in some cases, wearing a cycle
helmet will prevent a skull fracture.

Unlikely. *At those energies the helmet is receiving up to ten times its
maximum design energy and will fail catastrophically. *Second, at the
velocities associated with those energies, the additional mass of the
helmet strapped to the head adds about as much energy to the impact as
it absorbs if it works perfectly.

However the brain is most likely
to be damaged by a high g deceleration, whether or not the skull is
fractured, with a maximum short term tolerance of about 300 g for an
average person. Modern cycle helmets cushion the head so that they
limit the loading to about 200g in a reasonably survivable impact.

You know even less about neurology than you do about physics.
Coup-contrecoup injuries are not typically the problem.

Tony

You obviously haven't read the link I provided for Mark.

http://www.motorcyclistonline.com/ge...lmet_review/in....

I did, when I asked"
* *However the brain is most likely
* *to be damaged by a high g deceleration, whether or not the skull is
* *fractured, with a maximum short term tolerance of about 300 g for an
* *average person.

* Source?"

I expected a more rigorous source than a magazine article. You haven't
yet supplied your vector force diagram of a cyclist coming off "head
first" yet either , or even commented upon the physics of 100J equating
to a 10mph accident . Are you equipped to continue this discussion in
terms of physics, or as your critics point out is your contribution
simply to be arm waving and "commonsense"?- Hide quoted text -

- Show quoted text -

TRL PPR446 comes to more or less the same conclusions if you want
something more scientific. If you fall off a push bike or motorbike
and strike your head on the road surface, it matters little if you are
doing 5mph or 100mph, apart from subsequent minor abrasion injuries.

* Are you really trying to say that a helmet will have the same effect
if the 80Kg rider has 197J of Ke or 79000J ?

It's the height of the fall that is most significant, hence drop tests
are valid.

Is your physics up to giving figures for a 1.75M fall under 1G at 5mph
compered with a 1.75M fall at 100mph?

The vertical acceleration (deceleration) is the same in either case as
long as the road surface is flat and nothing else such as a kerbstone
is struck after the initial hit. The force of gravity remains
constant.


I can't find a Google reference to how many Joules a helmet will
absorb, as most papers refer to reducing g loadings.

"Most papers", are you sure? What papers have you read?

* Even if it is

100J, the important thing is that it is the initial 100J and
subsequent loadings on the brain will be reduced by this amount, even
if the helmet fails at this stage.

Really? so what happens if there is a 5mph blow to the head of a
stationary helmet wearer, does this mean that the "loading on the brain"
( forgetting the head's built in "shock absorbers") will be -87? How low
or high must the figure be to avoid brain damage?

Permanent brain damage starts at about 300g for more than a couple of
milliseconds. This reference includes a graph showing the difference
between a helmeted and unhelmeted head form.

If you apply the front brake hard at speed, the front wheel will act
as a fulcrum about which the whole bike and rider will rotate
(assuming the front tyre doesn't skid). Motorcyclists and BMX riders
make use of this effect to do stoppies, where the bike ends up
balanced on the front wheel (if you get it right!). See:

*http://www.youtube.com/watch?v=KlLjF...208922&playnex...

But where's the force vector diagram showing the rider coming off "head
first"? You are capable of producing one , aren't you? You wanted to use
physics to make your argument, I've yet to see you use any, do you
understand the principles and forces involved or do you simply cut and
paste words that you think will impress?-

Normally in a higher speed sudden stop, the rider will just be thrown
forward over the handlebars after a small amount of rotation.

Derek C

On Oct 2, 10:32*am, Marc wrote:

TRL PPR446 comes to more or less the same conclusions if you want
something more scientific. If you fall off a push bike or motorbike
and strike your head on the road surface, it matters little if you are
doing 5mph or 100mph, apart from subsequent minor abrasion injuries.

* Are you really trying to say that a helmet will have the same effect
if the 80Kg rider has 197J of Ke or 79000J ?

It's the height of the fall that is most significant, hence drop tests
are valid.

Is your physics up to giving figures for a 1.75M fall under 1G at 5mph
compered with a 1.75M fall at 100mph?


The vertical acceleration (deceleration) is the same in either case
as
long as the road surface is flat and nothing else such as a kerbstone
is struck after the initial hit. The force of gravity remains
constant.

I can't find a Google reference to how many Joules a helmet will
absorb, as most papers refer to reducing g loadings.

"Most papers", are you sure? What papers have you read?


Even if it is 100J, the important thing is that it is the initial 100J and
subsequent loadings on the brain will be reduced by this amount, even
if the helmet fails at this stage.


Really? so what happens if there is a 5mph blow to the head of a
stationary helmet wearer, does this mean that the "loading on the brain"
( forgetting the head's built in "shock absorbers") will be -87? How low
or high must the figure be to avoid brain damage?

Permanent brain damage starts at about 300g for more than a couple of
milliseconds. This reference includes a graph showing the difference
in g loading
between a helmeted and unhelmeted head form:

http://www.bhsi.org/foam.htm


If you apply the front brake hard at speed, the front wheel will act
as a fulcrum about which the whole bike and rider will rotate
(assuming the front tyre doesn't skid). Motorcyclists and BMX riders
make use of this effect to do stoppies, where the bike ends up
balanced on the front wheel (if you get it right!). See:


http://www.youtube.com/watch?v=KlLjF...208922&playnex...


But where's the force vector diagram showing the rider coming off "head
first"? You are capable of producing one , aren't you? You wanted to use
physics to make your argument, I've yet to see you use any, do you
understand the principles and forces involved or do you simply cut and
paste words that you think will impress?-


Normally in a higher speed sudden stop, the rider will just be thrown
forward over the handlebars after a small amount of rotation.

Derek C