weight KN and tonnes

[b101uk]

Bleedin hell nearly five tonne of force

 

How did you get the 4.8045 tonne from the 10kg:confused1:

 

the force ramps up dependent on how quick it stops (distence vs. time), you will note i said 1cm, if it stoped in 10cm it would be ~0.48045 tonne, if it stoped in 1m it would be ~0.048045 tonne or ~48.045kg(kgf), but all the above have a force of ~480.4595798J (also 480.4595798NM) for 10kg @ ~21.9279mph

[Arbocop]

ahhh goo old newton et al

 

b101uk is being hyper acurate, basically gavity is 9.8 m per second squared, the guy peter used gravity as 10ms2 whitch to be honest is what most do as makes the maths easy.

 

gravity accelerates just like when you put you foot down at the lights and the car takes off you are pusehed back in the seat untill the enjin reves out and you cant go any quicker gravity exACTLY THESAME SO IT WILL REACH TERMINAL VERLOCITY GIVEN ENOUGH ROOM TO FALL caps loc soz.

 

so just like in the car if you accelerate hard from the light but after 10 meters hit a wall the front of car would crumpel but you would be ok.

 

if in the car you had accelerated fo 30 m then hit a wall it may well kill you as there has been time for more energy to be added in, so the mass of the car plus the accelertion of the engin eqals the force you hit the wall with

 

a log dropping is just the sam its mass plus the acceleration of gravity add in the time (or distance the log dropps) that gravity has put energy in to the log and hay presto you get the force it can exert.

 

having said that what then plays is how you take the energy out of the log, 101 said stoped in a set distance so this can be calculated.

 

the longer you stop it and slower you take the force out the better well we all know that.........

 

lots of interesting stuff relating to this comming out of the rigging reserch and it will have influence on how we teach things, at the moment we do gesstimates for rigging 101 gave pure maths

 

just trust the maths is good and note the conversion to J joules thank god for metric, what id say is many years ago i left school with an o level phisics and forgot it all i then relert it for rigging, and it is fair to say that in rigging so many people put them seves at great risk as they just dont know how much danger they put them selves in front of.

 

im not sure if the above helped at all if not ill dig out another example for you, just remember what gets put in needs to come out...

 

kev

[nz paul]

big log falls it gona be heavy and hurt

 

simplified!

[desired_affect]

so is there a basic formula you can use to work this out???

[DriveLink]

Check out this page... it may help

 

Flatliners Southeast Climbing FAQ's - What's a Kilonewton?

[desired_affect]

Check out this page... it may help

 

Flatliners Southeast Climbing FAQ's - What's a Kilonewton?

basic im after a dummies guid to sort of thing, i was never good a physics.

[DriveLink]

This is one of those things where some of the problem lies with the way that we all use terms relating to mass and weight interchangeably.

 

Kilograms (kg) is actually a measure of mass.

 

Weight (kN) is mass multiplied by gravity.

 

So, W (weight) = m (mass) x g (gravity).

 

Fortunately, gravity is a constant, so that never changes - it's rounded off to a value of 9.81. (That's 9.81 metres per second squared).

 

W = m x 9.81

 

We'll measure mass in kilograms (kg) and weight in Newtons (N). So for something with a mass of 10kg...

 

W = 10 x 9.81

 

W = 98.1N

 

Let's try and make this even simpler by rounding off gravity to a value of 10 rather than 9.81, so we can now make a very quick rough estimate that if our karabiner says 25kN...

 

25kN = m x 10

 

or rewritten, that's the same as

 

m = 25kN / 10

 

m = 25000N / 10

 

m = 2500kg

 

or 2.5 tonnes approximately. Notice that I went from 25kN to 25000N as the 'k' represents a thousand of something.

 

I've got no idea if that actually helps or not! I hope so. In summary then,

 

1) Convert the kN value to N by multiplying it by 1000.

 

2) Divide that figure by 10.

 

3) Thats the weight in kg.

 

(If you want to be more accurate divide by 9.81 in 2) above).

[DrewB]

we measured an 80kg weight being dropped off a branch, attached to a rope by a standard length footlock strop. with this amount of slack the shock on the anchor was about 2 tonnes!

[desired_affect]

we measured an 80kg weight being dropped off a branch, attached to a rope by a standard length footlock strop. with this amount of slack the shock on the anchor was about 2 tonnes!

 

ruffly how long is the foot locking strop???

[DrewB]

ruffly how long is the foot locking strop???

 

id say roughly its over a metre, maybe 1.2m