Investigation of toppling ball flight in American football with a mechanical field-goal kicker     

Chase M. Pfeifer  Timothy J. Gay  Jeff A. Hawks  Shane M. Farritor  Judith M. Burnfield 《Sports Engineering》2018,21(2):95-102

A mechanical field-goal kicking machine was used to investigate toppling ball flight in American football place-kicking, eliminating a number of uncontrollable impact variables present with a human kicker. Ball flight trajectories were recorded using a triangulation-based projectile tracking system to account for the football’s 3-dimensional position during flight as well as initial launch conditions. The football flights were described using kinematic equations relating to projectile motion including stagnant air drag and were compared to measured trajectories as well as projectile motion equations that exclude stagnant air drag. Measured football flight range deviations from the non-drag equations of projectile motion corresponded to deficits between 9 and 31%, which is described by a football toppling compound drag coefficient of 0.007 ± 0.003 kg/m. Independent variables including impact location and impact angle orientation resulted in 15 impact conditions. We found that an impact location of 5.5 cm from the bottom of the ball maximized trajectory height and distance. At the 5.5-cm impact location, alterations in impact angle produced minimal change in football trajectory, including launch angle (range = 1.96 deg), launch speed (range = 1.06 m/s), and range (range = 0.94 m).  相似文献   

Mediating Our Knowledge     

Marie Jeanne Adams 《Curator: The Museum Journal》1983,26(4):275-286

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Cd-I and training: A perfect fit?     

Dawn L. Adams 《Performance Improvement》1995,34(6):28-33

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The Effect of Mobile Support Devices on the Anxiety and Self‐Efficacy of Hospital Float Staff     

Megan Riley McKee  Jeff M. Allen  Robin Tamez 《Performance Improvement Quarterly》2014,27(2):59-81

Floating is the act of staff moving from one unit to another based on the needs of the patients in a hospital. Many staff who float to different units express negative feelings, including anxiety and lack of self‐efficacy. However, floating is an economical and efficient method to use staff across the hospital, especially with current staffing shortages in the United States. This study investigated how the use of mobile performance support devices may help reduce anxiety and increase self‐efficacy for staff who float to different units. With access to multiple resources available on mobile devices, Bandura's social learning theory and self‐efficacy concept set the framework through modeling, observing, and imitating others in order to reproduce certain behaviors and tasks and believe in one's capability to perform. A quantitative study incorporating the retrospective pretest‐posttest design was conducted using the population of float staff, both nurses and respiratory therapists, from Children's Medical Center of Dallas. Both the State‐Trait Anxiety Inventory and General Self‐Efficacy Scale, along with a basic demographic tool, were used to explore anxiety and self‐efficacy in relation to the use of mobile performance support devices. Findings can be used to alleviate the negative feelings of staff toward the idea of floating.  相似文献   

Classification of all pharmacological interventions tested in trials relevant to people with schizophrenia: A study-based analysis     

Farhad Shokraneh  Clive E. Adams 《Health information and libraries journal》2023,40(2):201-216

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Testing the relationship between a need thwarting classroom environment and student disengagement     

Adigun  Olajumoke Beulah  Fiegener  Ashlyn M.  Adams  Curt M. 《European Journal of Psychology of Education - EJPE》2023,38(2):659-673

European Journal of Psychology of Education - National data on student disengagement show a pervasive trend that currently makes this phenomenon one of the biggest challenges faced by teachers...  相似文献