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Topic Date User

Rope - static v dynamic for top-roping and leading 30-Jan-2012 At 9:48:27 PM Dan Theman

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On 30/01/2012 Olbert wrote:

>Ummmm - no. No and no. Isaac Newton had a good deal to say about simple
>motion, the forces involved in climbing are just an application of his
>theory.

I was joking. Playing on the way OGH worded the sentence.
>
>Dynamic ropes absorb energy.
>Dynamic ropes do not absorb force.

humm you sure about this? Force = mass * acceleration. when you (mass) fall and accelerate due to gravity you generate a force. A large amount of this force is then absorbed by the rope (depending on how much is out of course) and is stored as potential energy in the rope.

>The peak level of force is less with a dynamic rope than a static because
>of the stretch.

So in other words it absorbs the force generated at one end resulting in a lower average force being felt at the other end.

>The force applied to the anchor point lasts longer with a dynamic rope.

fair enough. but it has a lower peak. If the force required to get the rope unstuck is more than the average then it doesn't matter how long you pull for. sometimes a sharp tug
is whats required.

>A statically applied force will result in the same resultant force at
>the other end for a static and dynamic rope.

Once the stretch is overcome in the dynamic (i.e hysteresis). So hanging on the rope
would be how you could produce this static force but this rules out the sharp tug which
may be required.

>Tugging on a dynamic will produce a lower peak force at the anchor point
>than a static, though I agree with ODH that this is probably negligible.
>
negligible? see above.