Cliff Diving (or Cliff Jumping)
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Imagine your body is accelerated to 70 mph within 2 seconds. Immediately afterwards you are slowed down to 0 mph within 0.7 seconds at a braking distance of 3.5 meters. When jumping from great heights the body is subjected to forces similar to those of a moderately severe accident, only a really well-trained body is able to cope with and resist these forces.
Many questions have been arised about the cliff diving or in our case, cliff jumping. I felt that it deserve to be recognized and notified about the safety and dangers of this experience. I do not encourage or insist that everyone jump off of cliffs, because of the high dangers. Since we will be in the mountains of West Virginia there are many cliffs that you may find to jump. Particularly last year we've found a location to jump. There are a couple points that people have jumped from ranging from 20-70 feet. In the following context I will further investigate the dangers and safety of jumping. I want everyone on this trip to have a safe and enjoyable trip. That is my biggest concern. Cliff jumping is EXTREMELY dangerous and should only be taken with careful precaution. Jumping from 20 feet is fairly safe, 50 feet could break bones, and 80 feet could KILL you! Since there is a cliff that is about 70 feet high, this height is very dangerous. I do not encourage anyone to jump from this height. There is also another cliff we can jump off of at about 25 feet. I suggest that everyone jumps from the smaller one, mainly and highly for safety. If you are jumping off of any cliffs regardless of height, please take and observe these tips very carefully. 1. DO NOT JUMP OFF OF ANY CLIFFS INTOXICATED! 2. DO NOT DIVE! 3. FROM HIGH HEIGHTS JUMP WITH ARMS TO YOUR SIDE AND LEGS POINTING DOWN (PENCIL DIVE)! 4. DO NOT FORCE/PUSH/SHOVE/RUSH ANYONE OFF OF ANY CLIFFS! 5. BE SAFE! Prior to jumping make sure that there are is no debri in the water where you are jumping. It may be good to check out the circumstances first, before jumping. The water is about 30-40 feet deep at the point of many jumps. Many common injuries of cliff jumping include severe bruises from the impact of hitting the water on an odd angle. There are many accounts of broken backs from simple entering the water wrong.
Below I 've done some calculations based on a video taken from last year's cliff jumping festivities. First you will see a video of the 70 foot jump. Below the video I have used some basic physics formulas to calculate the speed of impact and the height of the cliff. Taking the video from the heighest point of Glen’s foot to the point his foot hits the water is about 50 frames at 24 frames/second. Using this data we can calculate/estimate the following:
Using s = xo + vot +
So the cliff is about 21 meters or 70 feet high. Using vf2 = vo2 + 2as or vf =
So at the point your body hits the water you are traveling approximately 46 mph! |
to calculate height of the cliff:
to calculate the speed of impact with the water: