#### Woodwork

##### Well-Known Member

Looking for an online calculator to tell if mass x falls distance y, it creates z lbf of impact force.

Tried

but it is so virused and/or popuped out, I can't use it, and I don't think it even tells me what I want to know, anyway.

Trying to figure out how strong rigging needs to be to drop weight A distance B and brake over distance C. In other words, how many kN of force is generated when it stops/brakes.

I thought I'd found the answer here

but when I use all the same figures but increase the fall from 10m to 20m to 30m (not real world drops, was just inputting numbers to see if the calculator behaved as I expected), the fall energy in kN went up proportionally. (The calculator shows kN for 30 m fall being triple that for 10 m fall.) but I think it goes up exponentially – not proportionally – due to the acceleration of gravity.

If I'm not mistaken, tripling the fall distance should make the fall force 9X higher (3²), and quadrupling the fall distance should make the fall force 16X greater (4²) ... right? (All assuming a sudden stop, again, not real-world.)

Does anyone know where I could find a calculator for this, or maybe a simple equation that I could plug numbers into?

(This all started when I wondered how much force on my roof anchor I'd apply if I fell x feet before I unslacked and my prusik grabbed, the rope stretched and I stopped in y feet of deceleration.)

Thanks for any help.

Jeff

Tried

Trying to figure out how strong rigging needs to be to drop weight A distance B and brake over distance C. In other words, how many kN of force is generated when it stops/brakes.

I thought I'd found the answer here

but when I use all the same figures but increase the fall from 10m to 20m to 30m (not real world drops, was just inputting numbers to see if the calculator behaved as I expected), the fall energy in kN went up proportionally. (The calculator shows kN for 30 m fall being triple that for 10 m fall.) but I think it goes up exponentially – not proportionally – due to the acceleration of gravity.

If I'm not mistaken, tripling the fall distance should make the fall force 9X higher (3²), and quadrupling the fall distance should make the fall force 16X greater (4²) ... right? (All assuming a sudden stop, again, not real-world.)

Does anyone know where I could find a calculator for this, or maybe a simple equation that I could plug numbers into?

(This all started when I wondered how much force on my roof anchor I'd apply if I fell x feet before I unslacked and my prusik grabbed, the rope stretched and I stopped in y feet of deceleration.)

Thanks for any help.

Jeff

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