Go to Post Chances are it's an electrical or mechanical problem... - mechanicalbrain [more]
Home
Go Back   Chief Delphi > Technical > Technical Discussion
CD-Media   CD-Spy  
portal register members calendar search Today's Posts Mark Forums Read FAQ rules

 
Closed Thread
Thread Tools Rate Thread Display Modes
  #1   Spotlight this post!  
Unread 09-01-2010, 17:04
,4lex S.'s Avatar
,4lex S. ,4lex S. is offline
University Mentor
AKA: Alex Strong
FRC #2702 (REBotics)
Team Role: College Student
 
Join Date: Dec 2007
Rookie Year: 2004
Location: Waterloo, ON, Canada
Posts: 195
,4lex S. has much to be proud of,4lex S. has much to be proud of,4lex S. has much to be proud of,4lex S. has much to be proud of,4lex S. has much to be proud of,4lex S. has much to be proud of,4lex S. has much to be proud of,4lex S. has much to be proud of,4lex S. has much to be proud of
The Physics of a Kick

CD,

I have been thinking about how a team might model the mechanics of kicking a ball using highschool physics (or physics that could be taught quickly to FIRST students). If you want to take a shot at this problem on your own DO NOT CONTINUE READING POTENTIAL SPOILER ALERT. All I can come up with is the following:

1) Using Conservation of Energy, determine speed of kicker on contact with ball. (Given the likely use of rotating components, Kinetic rotational energy must be understood)
2) Using Conservation of Angular Momentum, determine the velocity* of the ball at the end of the collision. (Angular Momentum must be understood)
*One problem I notice is accounting for the end velocity of the kicker (Would this be treated as some form of elastic collision?)
3) Using Projectile Motion, figure out the characteristics of the balls flight.

This is definitely outside the bounds of the Ontario Grade 12 Physics Cirriculum, so my question is: can you come up with an easier model? I can also see some interesting other effects going on related to conservation of energy after the ball is released. This is a true test for young aspiring engineers to grapple with, so have fun!
__________________
University of Waterloo Mechanical Engineering Class of 2014- 2B School Term
University of Waterloo Formula SAE Race Team 2010-Eternity
FRC 2702: REBotics 2011 Mentor ::: FRC 1006: Fast Eddie Robotics 2005-2009 Alumni ::: FLL 4050: 2004 Alumni

  #2   Spotlight this post!  
Unread 09-01-2010, 17:16
mathking's Avatar
mathking mathking is offline
Coach/Faculty Advisor
AKA: Greg King
FRC #1014 (Dublin Robotics aka "Bad Robots")
Team Role: Teacher
 
Join Date: Jan 2005
Rookie Year: 1999
Location: Columbus, OH
Posts: 642
mathking has a reputation beyond reputemathking has a reputation beyond reputemathking has a reputation beyond reputemathking has a reputation beyond reputemathking has a reputation beyond reputemathking has a reputation beyond reputemathking has a reputation beyond reputemathking has a reputation beyond reputemathking has a reputation beyond reputemathking has a reputation beyond reputemathking has a reputation beyond repute
Re: The Physics of a Kick

Modeling the physics of a kick is going to depend a lot on modeling the spin (or lack thereof) of a soccer ball. For those who have played soccer, think of the toe ball versus striking the ball with the laces of your shoe.
__________________
Thank you Bad Robots for giving me the chance to coach this team.
Rookie All-Star Award: 2003 Buckeye
Engineering Inspiration Award: 2004 Pittsburgh, 2014 Crossroads
Chairman's Award: 2005 Pittsburgh, 2009 Buckeye, 2012 Queen City
Team Spirit Award: 2007 Buckeye, 2015 Queen City
Woodie Flowers Award: 2009 Buckeye
Dean's List Finalists: Phil Aufdencamp (2010), Lindsey Fox (2011), Kyle Torrico (2011), Alix Bernier (2013), Deepthi Thumuluri (2015)
Gracious Professionalism Award: 2013 Buckeye
Innovation in Controls Award: 2015 Pittsburgh
Event Finalists: 2012 CORI, 2016 Buckeye
  #3   Spotlight this post!  
Unread 09-01-2010, 17:48
JackG's Avatar
JackG JackG is offline
Internet is a series of ubertubes?
FRC #0001 (Juggernauts)
Team Role: College Student
 
Join Date: Nov 2006
Rookie Year: 2007
Location: Michigan, USA
Posts: 112
JackG is a splendid one to beholdJackG is a splendid one to beholdJackG is a splendid one to beholdJackG is a splendid one to beholdJackG is a splendid one to beholdJackG is a splendid one to beholdJackG is a splendid one to behold
Re: The Physics of a Kick

It seems to me that even those who have the physics experience to work this type of problem may not be able to do so until they know more of the variables. For instance, what is the weight and size of the soccer ball? How much is it inflated, and therefore what would be its coefficient of constitution? What is the friction between the soccer balls and the carpet? Of course someone with some serious skills in this area could set up the equation in terms of those variables, but we would still need to know this information eventually.

I'd take a crack at this, but this problem is too much for someone who hasn't taken their first college physics class yet.
__________________

Winners are ordinary people with Extraordinary Determination
  #4   Spotlight this post!  
Unread 09-01-2010, 19:25
Pneumaticsman's Avatar
Pneumaticsman Pneumaticsman is offline
Registered User
AKA: Mitch guzman
FRC #1566 (Ammoknights)
Team Role: Programmer
 
Join Date: Dec 2007
Rookie Year: 2007
Location: Idaho
Posts: 69
Pneumaticsman will become famous soon enoughPneumaticsman will become famous soon enough
Send a message via MSN to Pneumaticsman
Re: The Physics of a Kick

you could get extremely technical with this. First, you need to find out what type of gear motor ratio you will have. the motor specs will give you the max rpm, and from there, you would have to calculate the acceleration of the "foot" that kicks the ball. (I apologize i don't know the formula). Once you have the acceleration, you could probably somehow measure the angle of acceleration (how high the ball flies as you kick it). From there, all you have to do (neglecting the air pressure of the ball, and the air resistance) is find out how heavy the soccer ball is and you could measure everything else from there. Sorry I don't know the equations for the acceleration of the motor and angle of acceleration, but I'm only in high school myself haha
__________________


be prepared for the unexpected
  #5   Spotlight this post!  
Unread 09-01-2010, 19:27
Pneumaticsman's Avatar
Pneumaticsman Pneumaticsman is offline
Registered User
AKA: Mitch guzman
FRC #1566 (Ammoknights)
Team Role: Programmer
 
Join Date: Dec 2007
Rookie Year: 2007
Location: Idaho
Posts: 69
Pneumaticsman will become famous soon enoughPneumaticsman will become famous soon enough
Send a message via MSN to Pneumaticsman
Re: The Physics of a Kick

Quote:
Originally Posted by JackG View Post
It seems to me that even those who have the physics experience to work this type of problem may not be able to do so until they know more of the variables. For instance, what is the weight and size of the soccer ball? How much is it inflated, and therefore what would be its coefficient of constitution? What is the friction between the soccer balls and the carpet? Of course someone with some serious skills in this area could set up the equation in terms of those variables, but we would still need to know this information eventually.

I'd take a crack at this, but this problem is too much for someone who hasn't taken their first college physics class yet.
No kidding haha I'm trying to calculate the drag force of a model rocket, and it's kickin my butt lol
__________________


be prepared for the unexpected
  #6   Spotlight this post!  
Unread 09-01-2010, 20:37
jholland jholland is offline
Registered User
FRC #1329 (VIPRS)
Team Role: College Student
 
Join Date: Jan 2009
Rookie Year: 2003
Location: St. Louis
Posts: 5
jholland is an unknown quantity at this point
Re: The Physics of a Kick

I'm sure someone has found the coefficient of restitution for a soccer ball. That might help you out for a back of the napkin approach to the physics if you want to account for an inelastic collision between the ball and the kicker.

Last edited by jholland : 09-01-2010 at 20:49.
  #7   Spotlight this post!  
Unread 09-01-2010, 20:59
DonRotolo's Avatar
DonRotolo DonRotolo is offline
Back to humble
FRC #0832
Team Role: Mentor
 
Join Date: Jan 2005
Rookie Year: 2005
Location: Atlanta GA
Posts: 7,014
DonRotolo has a reputation beyond reputeDonRotolo has a reputation beyond reputeDonRotolo has a reputation beyond reputeDonRotolo has a reputation beyond reputeDonRotolo has a reputation beyond reputeDonRotolo has a reputation beyond reputeDonRotolo has a reputation beyond reputeDonRotolo has a reputation beyond reputeDonRotolo has a reputation beyond reputeDonRotolo has a reputation beyond reputeDonRotolo has a reputation beyond repute
Re: The Physics of a Kick

In a conservation of momentum equation, be sure to consider the momentum from the kicker that isn't imparted to the ball, instead being released into a collision with the robot frame.
__________________

I am N2IRZ - What's your callsign?
  #8   Spotlight this post!  
Unread 09-01-2010, 22:50
Bsteckler's Avatar
Bsteckler Bsteckler is offline
Resident computer tech
FRC #2402 (JamesMonroebotics)
Team Role: Programmer
 
Join Date: Nov 2007
Rookie Year: 2008
Location: Fredericksburg, VA
Posts: 56
Bsteckler has a spectacular aura aboutBsteckler has a spectacular aura about
Re: The Physics of a Kick

From my rough calculations, the kicker would need to operate at 110 ft/s and would require 188.4 lbs of force, this could be done with a 1.7 foot long cylinder at 60 psi and would shoot the ball 60 feet (about the diagonal length of the court) for a corner kick. Can someone please check these numbers?
__________________
"Don't try anything you are about to see us do at home, ever"
-The Mythbusters

2402 scores points.

  #9   Spotlight this post!  
Unread 18-01-2010, 06:58
freitagc freitagc is offline
Registered User
FRC #1713
 
Join Date: Jan 2010
Location: Clayton, NY
Posts: 1
freitagc is an unknown quantity at this point
Re: The Physics of a Kick

We are not familiar with pneumatics. What and where can we get a pneumatic device for our kicker?

Team 1713
  #10   Spotlight this post!  
Unread 18-01-2010, 08:46
IKE's Avatar
IKE IKE is offline
Not so Custom User Title
AKA: Isaac Rife
no team (N/A)
Team Role: Mechanical
 
Join Date: Jan 2008
Rookie Year: 2003
Location: Michigan
Posts: 2,151
IKE has a reputation beyond reputeIKE has a reputation beyond reputeIKE has a reputation beyond reputeIKE has a reputation beyond reputeIKE has a reputation beyond reputeIKE has a reputation beyond reputeIKE has a reputation beyond reputeIKE has a reputation beyond reputeIKE has a reputation beyond reputeIKE has a reputation beyond reputeIKE has a reputation beyond repute
Re: The Physics of a Kick

The simplest model I know is the ballistics model of parabolic flight. For a non-spiining ball, this has been pretty accurate (especially to the apex) for the foam poof balls, and for these soccer balls. It was quite inaccurate for the Moon-rocks as they had a ton more internal friction and much higher drag.

For ballasitics, you only neead a couple pieces of information.

Mass of the soccer-ball (410-450g)

Speed, Angle, distance, Apex (maximum).

*******************************
I did the math, but cut it out as I am not sure if the Original Poster wants the Math or not. If there is demand, I will post an example.
  #11   Spotlight this post!  
Unread 18-01-2010, 10:49
PICgnosis's Avatar
PICgnosis PICgnosis is offline
Registered User
AKA: Karen Suhm
FRC #0842 (Falcon Robotics)
Team Role: Mentor
 
Join Date: Jan 2006
Rookie Year: 2003
Location: Phoenix, AZ
Posts: 45
PICgnosis is on a distinguished road
Re: The Physics of a Kick

Here's a good article on the trajectory analysis of a soccer ball:
http://goff-j.web.lynchburg.edu/Goff_Carre_AJP_2009.pdf

I found it helpful.
  #12   Spotlight this post!  
Unread 18-01-2010, 15:38
Molten's Avatar
Molten Molten is offline
Registered User
AKA: Jason
FRC #1766 (Temper Metal)
Team Role: Mentor
 
Join Date: Dec 2006
Rookie Year: 2006
Location: Indiana
Posts: 2,289
Molten has a reputation beyond reputeMolten has a reputation beyond reputeMolten has a reputation beyond reputeMolten has a reputation beyond reputeMolten has a reputation beyond reputeMolten has a reputation beyond reputeMolten has a reputation beyond reputeMolten has a reputation beyond reputeMolten has a reputation beyond reputeMolten has a reputation beyond reputeMolten has a reputation beyond repute
Re: The Physics of a Kick

This post is long, I apologize. If you are interested in this topic, I believe my post is worth the time it will take to read it.

Something I haven't seen posted on here so far: Breaking the forces up into components. For this problem, it is much easier to understand if it is broken into vertical and horizontal components. If you can get an accurate reading of its horizontal speed, this speed is constant throughout the flight.(we are neglecting air resistance) Also, if you know the height the ball reaches you can find the initial vertical speed of the ball. This vertical speed won't be affected by the carpet because the carpet only affects the horizontal component.(directly) Now, once we have this...we can model its flight from the moment it leaves the ground to the moment it lands and the energy within the ball during this time. However, to model the actual kick...there is more to it. It really depends on how the kicker is designed, but I'm going with a leg with one joint. If you can find the speed it is rotating with, you can find the energy within the kicker upon impact. However, to do this math you must understand rotational inertia and angular speed. To explain angular speed, I'd suggest a merry go round. Explain how the linear speed changes with distance from the middle, but the angular speed is constant. As for rotational inertia, that is a bit harder. Try getting an item with high rotational inertia and an item with low rotational inertia. Put them both on a wheel or something and let them spin them. If the inertias are different enough, they will feel the difference in resistance. Ideally, they should have the same mass so they don't mistake the mass to being the sole cause of the increase in difficulty. Other then that, I'd just use a formula to calculate the actual rotational inertia of the kicker. Now, you can use the above data to find the energy in the kicker before the kick. This allows us to see the energy before the kick. We can now use the difference of energies(the ball after the kick, and the kicker before the kick) and we will see the energy lost due to the actual kick. Some of these losses were explained above in other posts. I'd go over them briefly with the student's but not go into too much depth on the actual math behind them.

Now, with the above explanation they get a thorough understanding of explaining what you can't understand by using what you can. Also, it teaches them rotational inertia by experiment(something my college never really did properly and is largely the reason it took so long for people to understand it). It also teaches them angular velocity which also confuses some if you don't get a good visual. After they understand all of this, they might be able to come up with a way to increase the distance of the ball by increasing the energy within the kicker prior to the kick. For instance, do we want a kicker with high rotational inertia? If so, how can we increase it? If not, how can we decrease it?

I know my explanation above explains alot of concepts that they don't go into fully in high school level physics. However, they are concepts that could be grasped by their age group with proper explanation and visuals. I chose these concepts because they are the concepts college kids sometimes don't understand, and ensures that your students will benefit greatly from the experience. If nothing else, exposing them to these ideas will have a positive effect.

If anyone has questions, feel free to PM me. Also, if some part of this is wrong(I'm pretty sure all the concepts are there) please respond immediately.
__________________
"Curiosity. Not good for cats, great for scientists."- Numb3rs

"They can break your cookie, but... you'll always have your fortune."-T.W. Turtle, Cats Don't Dance

"Tell my tale to those who ask. Tell it truly - the ill deeds along with the good, and let me be judged accordingly. The rest... is silence."-Dinobot, Beast Wars

"Though the first step is the hardest and the last step ends the quest, the long steps in between are certainly the best."
–Gruffi Gummi, Disney's Adventures of the Gummi Bears
  #13   Spotlight this post!  
Unread 18-01-2010, 19:33
Alan Anderson's Avatar
Alan Anderson Alan Anderson is offline
Software Architect
FRC #0045 (TechnoKats)
Team Role: Mentor
 
Join Date: Feb 2004
Rookie Year: 2004
Location: Kokomo, Indiana
Posts: 9,113
Alan Anderson has a reputation beyond reputeAlan Anderson has a reputation beyond reputeAlan Anderson has a reputation beyond reputeAlan Anderson has a reputation beyond reputeAlan Anderson has a reputation beyond reputeAlan Anderson has a reputation beyond reputeAlan Anderson has a reputation beyond reputeAlan Anderson has a reputation beyond reputeAlan Anderson has a reputation beyond reputeAlan Anderson has a reputation beyond reputeAlan Anderson has a reputation beyond repute
Re: The Physics of a Kick

Quote:
Originally Posted by freitagc View Post
We are not familiar with pneumatics. What and where can we get a pneumatic device for our kicker?
The Pneumatics Manual will answer both of these questions and more. Find it listed under Section 8 of the Game Manual on the FIRST web site.

http://www.usfirst.org/roboticsprogr...nt.aspx?id=452
Closed Thread


Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Numpty Physics: a crayon-drawing physics game JohnBoucher Robotics Education and Curriculum 0 09-06-2009 15:41
The physics behind trackball inflation octothorpe General Forum 6 09-01-2008 16:27
The speed of light is NOT a constant?! A milestone in Physics? KenWittlief Math and Science 37 23-08-2006 00:49
The AP Physics Last Minute Meeting Keith Chester Chit-Chat 6 08-05-2005 21:38
The physics of... soccer balls? Gui Cavalcanti Chit-Chat 9 18-08-2002 16:19


All times are GMT -5. The time now is 20:18.

The Chief Delphi Forums are sponsored by Innovation First International, Inc.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
Copyright © Chief Delphi