Oblique impact of a hard ball on a soft surface

Cross, Rod

doi:10.1088/1361-6404/ac221e

Cited by 3 publications

(2 citation statements)

References 10 publications

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“…The control group did not perform Tai Chi soft ball exercise and maintained the original living state. 4,5…”

Section: Research Objectmentioning

confidence: 99%

Influence of Tai Chi Softball on Body Composition and Bone Density

2023

Rev Bras Med Esporte

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Introduction Tai Chi Softball fully reflects the most complete and coherent concept of Tai Chi exercise, round and smooth, natural and continuous, and is very suitable for the daily exercise of middle-aged and elderly people. Objective Explore the effect of Tai Chi Softball exercise on body shape and bone mineral density of middle-aged and elderly women. Methods 45 volunteers were recruited and divided into a Tai Chi Softball group and a control group; the Tai Chi Softball group was guided by professional trainers to perform Tai Chi Softball exercises for six months. The control group did not perform Tai Chi Softball exercises and tested various physical indicators for comparison. Results The weight and BMI of middle-aged and elderly women showed a decreasing trend. The abdominal and arm skinfold measurements were significantly different from those before the experiment (P < 0.01). Body fat percentage decreased significantly, and muscle weight increased, showing statistical significance (P < 0.05). Conclusion Tai Chi Softball exercise can alleviate the rapid decline in bone mineral density and bone mineral content in middle-aged and elderly women. Level of evidence II; Therapeutic studies - investigation of treatment outcomes.

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“…The control group did not perform Tai Chi soft ball exercise and maintained the original living state. 4,5…”

Section: Research Objectmentioning

confidence: 99%

Influence of Tai Chi Softball on Body Composition and Bone Density

2023

Rev Bras Med Esporte

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“…rubber-based) surfaces has been investigated to a lesser extent. In this context, the research focused on the effects of impact angle and high impact velocity [9][10][11][12][13]. Some research was concerned with impact protective coatings made from polymers [14][15][16].…”

Section: Introductionmentioning

confidence: 99%

Tunable rebound of millimeter-sized rigid balls by magnetic actuation of elastomer-based surface microstructures

Kriegl,

Jezeršek,

Kravanja

et al. 2024

Smart Mater. Struct.

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A novel method for controlling the rebound behavior of small balls made of Al2O3 with a radius of 2.381 mm is presented. It uses different types of micro-structured surfaces of soft magnetoactive elastomers. These surfaces were fabricated via laser micromachining and include fully ablated surfaces as well as micrometer-sized lamellas with a fixed width of 90 µm, height of 250 µm and three different gap sizes (15, 60 and 105 µm). The lamellas can change their orientation from edge-on to face-on configuration according to the direction of the external magnetic field from a permanent magnet. The orientation of the external magnetic field significantly influences the rebound behavior of the balls, from a coefficient of restitution e of ≈ 0.5 to < 0.1. The highest relative change in the coefficient of restitution between zero field and face-on configuration of ≈ 80 % is observed for lamellas with a gap of 60 µm. Other characteristics of the ball rebound such as the penetration depth into an Magnetoactive elastomer and the maximum deceleration are investigated as well. The proposed method does not require a constant power supply due to the use of permanent magnets. It may find novel applications in the field of impact engineering.

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Bounce of a golf ball on the green

Cross

2023

Proceedings of the Institution of Mechanical Engineers, Part P:

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A ball incident on a horizontal surface with backspin can rebound forwards or backwards depending on the angle of incidence and the amount of backspin. The ball can also bounce forwards several times before it bounces backwards. The outcome depends on whether the ball slides throughout the impact or whether the ball grips the surface during the impact. The physics of the bounce of a golf ball on a green is described in the present article and estimates are given of the stopping distance after the ball first lands on the green, based on experimental bounce data.

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Oblique impact of a hard ball on a soft surface

Cited by 3 publications

References 10 publications

Influence of Tai Chi Softball on Body Composition and Bone Density

Influence of Tai Chi Softball on Body Composition and Bone Density

Tunable rebound of millimeter-sized rigid balls by magnetic actuation of elastomer-based surface microstructures

Bounce of a golf ball on the green

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