Finite Element Modeling and Experimental Study Of
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USTA Parents Guide to 10 and Under Tennis
10 AND UNDER TENNIS A Parents Guide 10andUnderTennis.com little activity, your child is unlikely to develop a love of the game Chapter 1: Introduction and will instead find another activity that is more compelling. Parents want to do what is best for their children. They want to Long-term goals include the enjoyment of an activity they can play provide meaningful and positive experiences that will be enjoyable for a lifetime. It is a game kids can play with friends and family. and lead to the positive development of the child. Tennis is a sport Tennis is a fantastic way to spend quality time as a family. that a child can learn at a young age and enjoy with friends and Be aware of putting pressure on children for results, but make family for a lifetime. This guide will provide you with the right tools sure you recognize and acknowledge effort. In this country, 70 to get your child started correctly, keeping the focus on the fun, percent of kids quit organized sport by the age of 13, and the top active and lifelong benefits of tennis. three reasons given by kids are: Goals 1. It’s not fun anymore It is important to keep participation in youth sports in perspective and 2. Parental pressure to perform to understand why kids play. Many times adults have grand ideas of a 3. Unmet coaching expectations professional career or even a college scholarship. While these could be long-term goals for those players who eventually specialize in a sport, children play for different reasons. -
The Bouncing Ball Apparatus As an Experimental Tool
1 The Bouncing Ball Apparatus as an Experimental Tool Ananth Kini Aerospace and Mechanical Engineering, University of Arizona Tucson, AZ 85721, USA Thomas L. Vincent Aerospace and Mechanical Engineering, University of Arizona Tucson, AZ 85721, USA Brad Paden Mechanical and Environmental Engineering, University of California, Santa Barbara, CA 93106, USA. Abstract The bouncing ball apparatus exhibits a rich variety of nonlinear dynamical behavior and is one of the simplest mechanical systems to produce chaotic behavior. A computer control system is designed for output calibration, state determination, system identification and control of the bouncing ball apparatus designed by Launch Point Technologies. Two experimental methods are used to determine the co- efficient of restitution of the ball, an extremely sensitive parameter of the apparatus. The first method uses data directly from a stable 1-cycle orbit. The second method is based on the ball map combined with data from a stable 1-cycle orbit. For control purposes, two methods are used to construct linear maps. The first map is determined by collecting data directly from the apparatus. The second map is determined from linearization of the ball map. The maps are used to estimate the domains of attraction to the stable 1-cycle orbit. These domains of attraction are used with a chaotic control algorithm to control the ball to a stable 1-cycle, from any initial state. Results are compared and it is found that the linear map obtained directly from the data gives the more accurate representation of the domain of attraction. 1 Introduction The bouncing ball system consists of a ball bouncing on a plate whose amplitude is fixed and the frequency of vibration is controlled. -
Ball Change in Tennis: How Does It Affect Match Characteristics and Rally Pace in Grand Slam Tournaments?
Original Article Ball change in tennis: How does it affect match characteristics and rally pace in Grand Slam tournaments? JAN CARBOCH 1 , MATEJ BLAU, MICHAL SKLENARIK, JAKUB SIMAN, KRISTYNA PLACHA Department of Sport Games, Faculty of Physical Education and Sport, Charles University, Prague, Czech Republic ABSTRACT Tennis balls degrade after fast racket and ground impacts until they are changed after agreed number of games. The aim is to analyse the new (after the ball change) and used balls (prior to the ball change) match characteristics and the frequency of rally shots in matches in the Australian Open, French Open and Wimbledon in 2017. Paired samples t-tests and Cohen d were used to compare the point duration, number of rally shots, time between the points, rally pace and work to rest ratio among these tournaments. There was a significant difference in rally shots number played with the new balls (4.17 ± 0.86) compared to the used balls (4.60 ± 1.10) in female matches (p = 0.047); in males matches large effect size was found (d = - 0.83) in the same variable with the new balls (4.44 ± 0.57) and used balls (4.95 ± 0.66), both happened in the Australian Open. No difference was found between the new and used balls in the rally pace in all the observed events. The Wimbledon match characteristics were least affected by the ball change. The ball degradation affected the match characteristic the most in the Australian Open, in terms of more rally shots, but not slowing down the rally pace. -
Judy Murray Tennis Resource – Secondary Title and Link Description Secondary Introduction and Judy Murray’S Coaching Learn How to Control, Cooperate & Compete
Judy Murray Tennis Resource – Secondary Title and Link Description Secondary Introduction and Judy Murray’s Coaching Learn how to control, cooperate & compete. Philosophy Start with individual skill, add movement, then add partner. Develops physical competencies, such as, sending and receiving, rhythm and timing, control and coordination. Children learn to follow sequences, anticipate, make decisions and problem solve. Secondary Racket Skills Emphasising tennis is a 2-sided sport. Use left and right hands to develop coordination. Using body & racket to perform movements that tennis will demand of you. Secondary Beanbags Bean bags are ideal for developing tracking, sending and receiving skills, especially in large classes, as they do not roll away and are more easily trapped than a ball. Start with the hand and mimic the shape of the shot. Build confidence through success and then add the racket when appropriate. Secondary Racket Skills and Beanbags Paired beanbag exercises in small spaces that are great for learning to control the racket head. Starting with one beanbag, adding a second and increasing the distance. Working towards a mini rally. Move on to the double racket exercise which mirrors the forehand and backhand shots - letting the game do the teaching. Secondary Ball and Lines Always start with the ball on floor. Develop aiming skills by sending the ball through a target area using hands first before adding the racket. 1 Introduce forehand and backhand. Build up to a progressive floor rally. Move on to individual throwing and catching exercises before introducing paired activity. Start with downward throw emphasising V-shape, partner to catch after one bounce. -
Discrete Dynamics of a Bouncing Ball
Discrete Dynamics of a Bouncing Ball Gilbert Oppy Dr Anja Slim Monash University Contents 1 Abstract 2 2 Introduction - Motivation for Project 2 3 Mathematical Model 3 3.1 Mathematical Description . .3 3.2 Further Requirements of Model . .4 3.3 Non-Dimensionalization . .4 4 Computational Model 5 5 Experimental Approach 6 5.1 General Use of Model . .6 5.2 Focusing on the α = 0.99 Case . .7 5.3 Phase Plane Analysis . .8 5.4 Analytically Finding 1-Periodic Bouncing Schemes . .9 6 Phase Space Exploration 10 6.1 A 1-Periodic regime in Phase Space . 10 6.2 Other Types of Periodic Bouncing . 11 6.3 Going Backwards in Time . 13 7 Bifurcations Due to Changing the Frequency !∗ 15 7.1 Stability Analysis for 1-Periodic Behaviour . 15 7.2 Bifurcations for the V ∗ = 3 1-Periodic Foci . 16 8 Conclusion 20 9 Acknowledgements 21 1 1 Abstract The main discrete dynamics system that was considered in this project was that of a ball bouncing up and down on a periodically oscillating infinite plate. Upon exploring this one dimensional system with basic dynamical equations describing the ball and plate's vertical motion, it was surprising to see that such a simple problem could be so rich in the data it provided. Looking in particular at when the coefficient of restitution of the system was α = 0.99, a number of patterns and interesting phenomena were observed when the ball was dropped from different positions and/or the frequency of the plate was cycled through. Matlab code was developed to first create the scenario and later record time/duration/phase of bounces for very large number of trials; these programs generated a huge array of very interesting results. -
Bouncing Balls Summer of Innovation Zero Robotics Bouncing Balls Instructor’S Handout
Physics: Bouncing Balls Summer of Innovation Zero Robotics Bouncing Balls Instructor's Handout 1 Objective This activity will help students understand some concepts in force, acceleration, and speed/velocity. 2 Materials At least one bouncy ball, such as a superball or a tennis ball. If you want, you can bring more balls for the students to bounce themselves, but that's not critical. 3 Height Bounce a superball many times in the front of the classroom. Ask the students to call out observations about the ball and its bouncing. Things to observe include: • The ball's starting acceleration and speed are 0; • The ball's acceleration and speed increase until the ball hits the ground and bounces; • After the bounce, the ball returns to a maximum height that is less than the original height of the ball Questions to ask: • What forces are acting on the ball? (Answer: gravity. friction, the normal force) • Where does the ball reach its maximum speed and acceleration? (Answer: right before it hits the ground) • What is the acceleration of the ball when it is at its peak heights? (Answer: Zero...it's about to change direction 4 Applications 4.1 Tall Tower What happens when you drop a bouncy ball off of a gigantic building, such as the Sears Tower in Chicago (440 m), or the new tallest building in the world, the Burj Khalifa in Dubai (500 m)? Well, some Australian scientists dropped a bouncy ball off of a tall radio tower. The ball actually shattered like glass on impact. 4.2 Sports What sports require knowledge of bouncing balls for their success? (Tennis, cricket, racquetball, baseball, and basketball are a few). -
Nassau Sports Product Catalog
2019 www.nassau.co.kr NASSAU SPORTS E - mail : [email protected] Tel : +82-70-4493-4577 Fax : +82-32-326-2570 PRODUCT CATALOG Address : Nassau B/D, 42, Bogwang-ro 106beon-gil, Deogyang-gu,Goyang-si, Gyeonggi-do, Republic of Korea Since our foundation in 1971 as a company specializing in sporting goods, we have been endeavoring hard to keep our technology state-of-the-art and provide our custom- ers the best service they can get in the industry. In an effort to do so, we could manage to get appointed as an official match ball supplier for several international tournaments: 86 Asian Games for tennis, soccer, handball and volleyball, 88 Olympics Games for tennis and 4 Grand Slam tournaments for tennis. In addition, we got our balls interna- tionally approved by world-renowned sports federations such as International Tennis Federation(ITF), Fédération Internationale de Volleyball(FIVB), International Handball Federation(IHF), Fédération Internationale de Football Association(FIFA) and Korea Football Association(KFA). 028 Volleyball Section 1 04 History Section 5 029 PATRIOT 3000 / NEW PATRIOT(VNP) 030 AERO DYNAMIC(VAD) / POWER DYNAMIC(VPD) / ATTACK(VA) Section 2 06 Soccer Ball / Futsal Ball / Handball / Rugby Ball 08 TUJI FA “New Technology of 4 Panel” 010 TUJI FA (SSTG-5FF) 011 TUJI PREMIUM(SSTG-P) / TUJI PREMIUM(SSTP) / TUJI(SSTG-5) Section 6 032 Tennis Racket / Badminton Racket / Shuttlecock / Padminton 012 NEW TUJI(SSHTJ) / TUJI(SSNTJ) / TUJI 88(SBT88) 034 SENIOR TOUR / SENIOR TEAM / OPTIMUM PRO 013 TUJI TRAPPER(SBTR) / CHAMPIONSHIP -
Return to Competition: Individual Sport Considerations
Pennsylvania Interscholastic Athletic Association Return to Competition: Individual Sport Considerations Pennsylvania Interscholastic Athletic Association National Federation of State High School Associations Pennsylvania Department of Education Pennsylvania Department of Health Sports Medicine Advisory Committee TABLE OF CONTENTS General Considerations for All Sports ..................................................................................................................... 2 General Considerations for Officials ....................................................................................................................... 7 General Considerations for Fall Sports: Cross Country ........................................................................................................................................... 11 Field Hockey ............................................................................................................................................. 12 Football .................................................................................................................................................... 14 Golf ........................................................................................................................................................... 17 Soccer ....................................................................................................................................................... 18 Tennis ...................................................................................................................................................... -
Towel Flip Standing Long Jump
Foot Bottle Flip Trap Shoe Flip Spoon Your Flip Relay Lid Soccer Towel Flip Water Bottle Scooter Pillow Bowl Ball Bullseye Race Trap Stack The Backboard Sneakers Bank It Stacks & Jacks Fan Favorite Shoe Balance Standing Pillowcase Sock-er Long Jump Penguin Race Sack Race Keep it Up Skee-Ball Shoe Flip Back Click Here for Video Demonstration Equipment- 1 Sneaker, Open Space, timer/stopwatch Set Up- Make sure you have plenty of open space around you. 1 Point Directions: ● How many points can you score in a minute. 2 Points ● Put your sneaker on just over your toes. ● When timer starts, flick your shoe off your foot. ● 1pt- sneaker lands on side; 2 pts- sneaker lands 3 Points upright; 3 pts- sneaker lands upside down ● 0pts- sneaker hits the ceiling/fan/knocks something over. ● Write your score on Field Day Scorecard. Click Here for Video Stack the Sneakers Back Demonstration Equipment- 10-15 pairs of sneakers of sneakers/shoes, item to create home base (plate, cone, cup) Set Up- Make a pile of shoes/sneakers in the middle of players. Place home bases equal distance from shoe pile. Directions: ● Object is to stack the sneakers/shoes on top of one another to create a tall stack of shoes. ● When signal begins, go to stack and take 1 shoe/sneaker and place it on your home base. ● Repeat taking 1 shoe/sneaker at a time until all sneakers/shoes are gone from the middle pile ● It is okay if your stack falls. Fix the stack before you go and get another shoe. -
Striking Results with Bouncing Balls
STRIKING RESULTS WITH BOUNCING BALLS André Heck, Ton Ellermeijer, Ewa K ędzierska ABSTRACT In a laboratory activity students study the behaviour of a bouncing ball. With the help of a high-speed camera they can study the motion in detail. Computer modelling enables them to relate the measurement results to the theory. They experience that reality (measurements) is not automatically in line with the predictions of the theory (the models), but often even strikingly apart. This stimulates a process of repeated cycles from measurement to interpretations (how to adapt the model?), and in this way it realizes a rich and complete laboratory activity. The activity is made possible by the integrated ICT tools for measurements on videos made by a high-speed camera (via point-tracking), and for modelling and simulations. KEYWORDS Video recording and analysis, computer modelling, simulation, animation, kinematics, bouncing ball INTRODUCTION Each introductory physics textbook, already at secondary school level, illustrates Newton’s laws of motion and concepts of gravitational energy and kinetic energy with examples of objects dropped or thrown vertically and contains investigative activities about falling objects. The reasons are obvious: o the physics and mathematics is still simple enough to be accessible to most of the students; o an experiment with a falling object, in which data are collected with a stopwatch and meter stick, using sensors such as a microphone or a sonic ranger (MBL), or via web cams and video analysis tools (VBL), is easy to perform; o it is a clear invitation to compare measurements with theoretical results. Falling with air resistance is a natural extension of a free fall study. -
Measurements of the Horizontal Coefficient of Restitution for a Superball and a Tennis Ball
Measurements of the horizontal coefficient of restitution for a superball and a tennis ball Rod Crossa) Physics Department, University of Sydney, Sydney, NSW 2006 Australia ͑Received 9 July 2001; accepted 20 December 2001͒ When a ball is incident obliquely on a flat surface, the rebound spin, speed, and angle generally differ from the corresponding incident values. Measurements of all three quantities were made using a digital video camera to film the bounce of a tennis ball incident with zero spin at various angles on several different surfaces. The maximum spin rate of a spherical ball is determined by the condition that the ball commences to roll at the end of the impact. Under some conditions, the ball was found to spin faster than this limit. This result can be explained if the ball or the surface stores energy elastically due to deformation in a direction parallel to the surface. The latter effect was investigated by comparing the bounce of a tennis ball with that of a superball. Ideally, the coefficient of restitution ͑COR͒ of a superball is 1.0 in both the vertical and horizontal directions. The COR for the superball studied was found to be 0.76 in the horizontal direction, and the corresponding COR for a tennis ball was found to vary from Ϫ0.51 to ϩ0.24 depending on the incident angle and the coefficient of sliding friction. © 2002 American Association of Physics Teachers. ͓DOI: 10.1119/1.1450571͔ I. INTRODUCTION scribed as fast, while a surface such as clay, with a high coefficient of friction, is described as slow. -
Follow the Bouncing Ball When an Object Is Freely Falling, Physics Tells Us That It Has Constant Downward Acceleration
Calculus 1 – Spring 2008 Dr. Hamblin Section 2.5: Follow the Bouncing Ball When an object is freely falling, physics tells us that it has constant downward acceleration. If is the function that describes the height of the ball after t seconds, then the acceleration is given by or . For this example, we’ll use feet instead of meters. Using antiderivatives, we can now find formulas for h and h: The values of and depend on the initial position and initial velocity of the object. We will use these formulas to analyze a ball being dropped off of a balcony. When the ball bounces, it loses some of its energy, and rises at a slower speed than it fell. We want to measure this effect, so first we need to collect some data. We will drop a ball off of the balcony, and measure the time it takes to hit the ground the first time and the second time. Trial # 1 2 3 4 Average First bounce Second bounce Let be the average time until the first bounce, and let be the average time until the second bounce. We want to use the data for and to compute the unknown constants and above. However, when the ball bounces, its motion changes, so we will have to compute and once for the function describing the motion of the ball before the first bounce, and again for the function describing the motion of the ball between bounces. So is a piecewise function, as shown below. Calculus 1 – Spring 2008 Dr. Hamblin Before the First Bounce We would like to find the values of and so that we can understand the first “piece” of our function.