A jumping cylinder on an inclined plane

Gómez, R.; Hernández-Gómez, J. J.; Marquina, V

doi:10.1088/0143-0807/33/5/1359

Cited by 10 publications

(14 citation statements)

References 8 publications

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“…24,25 In a MG in an open space, this movement will frequently be in a circular motion due to the rotational dynamics caused by the center point creating a torque of inertia. 26 In a closed space with high crowd density, the motion described can be accentuated with any nozzle-like architectural design. 27 Progression leads to motion failure along the XY-axis with high-pressure stagnation on the unit mass.…”

Section: Inelastic Collisionmentioning

confidence: 99%

Use of Dimensional Analysis in the X-, Y-, and Z-Axis to Predict Occurrence of Injury in Human Stampede

Alhadhira

Molloy

Casasola

et al. 2019

Disaster med. public health prep.

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Background:Human stampedes (HS) may result in mass casualty incidents (MCI) that arise due to complex interactions between individuals, collective crowd, and space, which have yet to be described from a physics perspective. HS events were analyzed using basic physics principles to better understand the dynamic kinetic variables that give rise to HS.Methods:A literature review was performed of medical and nonmedical sourced databases, Library of Congress databases, and online sources for the term human stampedes resulting in 25,123 references. Filters were applied to exclude nonhuman events. Retrieved references were reviewed for a predefined list of physics terms. Data collection involved recording frequency of each phrase and physics principle to give the final proportions of each predefined principle used a single-entry method for each of the 105 event reports analyzed. Data analysis was performed using the R statistics packages “tidyverse”, “psych”, “lubridate”, and “Hmisc” with descriptive statistics used to describe the frequency of each observed variable.Results:Of the 105 reports of HS resulting in injury or death reviewed, the following frequency of terms were found: density change in a limited capacity, 45%; XY-axis motion failure, 100%; loss of proxemics, 100%; deceleration with average velocity of zero, 90%; Z-axis displacement pathology (falls), 92%; associated structure with nozzle effect, 93%; and matched fluid dynamic of high pressure stagnation of mass gathering, 100%.Conclusions:Description or reference to principles of physics was seen in differing frequency in 105 reports. These include XY-axis motion failure of deceleration that leads to loss of human to human proxemics, and high stagnation pressure resulting in the Z-axis displacement effect (falls) causing injury and death. Real-time video-analysis monitoring of high capacity events or those with known nozzle effects for loss of proxemics and Z-axis displacement pathology offers the opportunity to prevent mortality from human stampedes.

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Section: Inelastic Collisionmentioning

confidence: 99%

Use of Dimensional Analysis in the X-, Y-, and Z-Axis to Predict Occurrence of Injury in Human Stampede

Alhadhira

Molloy

Casasola

et al. 2019

Disaster med. public health prep.

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“…We develop the analysis of the harmonic and the anharmonic regimes of oscillation of the spool when an increasing number of extra masses is added and discuss how the normal force, which determines the value of the friction force, is not equal to the weight of the spool and depends on its motion. As a consequence, the system can lose grip and start slipping [2,3] (for the same reason the spool can jump when it is rolling down an inclined plane [4,5]).…”

mentioning

confidence: 99%

The surprising rolling spool: librational motion and failure of the pure rolling condition

Onorato¹,

Malgieri²,

Mascheretti³

et al. 2015

Eur. J. Phys.

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In a previous work (Onorato P, Malgieri M, Mascheretti P and De Ambrosis A 2014 The surprising rolling spool: experiments and theory from mechanics to phase transitions Eur. J. Phys. 35 055011) an asymmetric rolling spool (ARS) was investigated as a simple model for a second-order phase transition. Here, we deepen the study of this system to address critical aspects related both to the characteristic of the oscillatory anharmonic motion and to the role of friction forces in determining it. The experimental data show that for largely asymmetric bodies the rolling condition is not reliably fulfilled because the intensity of the friction force goes below the needed value to ensure rolling without slipping.

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“…The analysis assumed so far a perfect rolling motion without any slipping. Though this is appropriate for a theoretical study, real bodies might in fact slip or even lift of the support plane [14]. A common physical model is to employ the static friction coefficient to formulate a physical no-slip condition based on the constraint acceleration a acting at the contact point:…”

Section: Slippingmentioning

confidence: 99%

Tautochrone and Brachistochrone Shape Solutions for Rocking Rigid Bodies

Glaschke

2016

Preprint

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Rocking rigid bodies appear in several shapes in everyday life: As furniture like rocking chairs and rocking cradles or as toys like rocking horses or tilting dolls. The familiar rocking motion of these objects, a non-linear combination of a rigid rotation and a translation of the center of mass, gives rise to a number of interesting dynamical properties. However, their study has received little attention in the literature.This work presents a comprehensive introduction to the dynamics of rocking rigid bodies, including a concise derivation of the equations of motion as well as a general inversion procedure to construct rocking rigid body shapes with specified dynamical properties. Moreover, two novel rigid body shapes are derived -the tautochrone shape and the brachistochrone shape -which represent an intriguing generalization of the well-know tautochrone and brachistochrone curves. In particular, tautochrone shapes offer an alternative construction of a tautochrone pendulum, in addition to Huygens' cycloid pendulum solution.

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A jumping cylinder on an inclined plane

Cited by 10 publications

References 8 publications

Use of Dimensional Analysis in the X-, Y-, and Z-Axis to Predict Occurrence of Injury in Human Stampede

Use of Dimensional Analysis in the X-, Y-, and Z-Axis to Predict Occurrence of Injury in Human Stampede

The surprising rolling spool: librational motion and failure of the pure rolling condition

Tautochrone and Brachistochrone Shape Solutions for Rocking Rigid Bodies

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