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Name: Richard W.
Status: educator
Age: 40s
Location: N/A
Country: N/A
Date: Saturday, July 06, 2002


Question:
Hello! I am interested in finding out if anyone has an explanation for a phenomenon that my students and I have observed on a number of different free-fall amusement park rides: A penny, whether held in the hand or placed in a closed container (plastic peanut butter jar with lid screwed on, for example), will often float up from the surface upon which it has been resting while the ride "free-falls".

We have discussed this phenomenon in my classes many times, and some students feel that the ride, in order to give you an extra thrill, actually accelerates you down at a rate greater than 9.80 m/s^2, which would cause the ride's car to pull out from underneath the quarter. Others have suggested the possibility that there is some sort of latching mechanism that requires the car to actually be mechanically lifted up right before releasing. If the car were to be lifted up in this fashion, the quarter would be lifted with it, effectively giving it a small "toss into the air" just before the car accelerates down from underneath it.

I have not been able to speak with any ride engineers to discuss this problem. Any ideas?


Replies:
Richard:

1. THIS IS A DANGEROUS PRACTICE! We strongly urge you NOT to let your students do this. If the unteathered object is not caught, it can be fatal to someone on the ground. NEVER DO THIS!

2. This has been observed using electronic accelerometers. There seem to be several reasons for this: On some rides, the release mechanism pulls the ride up a few millimeters as part of its action, and then you fall. There is a physiological response to fear that at the moment of release, the body tenses, and the slight upward jolt is noticed.

I recently was having a detailed discussion about issues in free fall. There are acoustical considerations and perhaps torques involved, too.

3. Unless you are on one of the new compressed air rides built by Ingersoll-Rand, you are not being "shot" down.

Please do not every do this dangerous experiment. This is a very serious safety violation that may have severe results.

Nathan A. Unterman



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