Making Sport of Physics

Can Peyton Manning run 17 mph?

That was the question put to me by the Tampa Bay Times.  During the AFC title game in which Manning’s Broncos defeated the Patriots, a replay showed Manning running for a first down in the 3rd quarter and hitting 17 mph (27 kph) on a speedometer graphic.  To test the NFL’s speed claim, I needed to analyse video of the play.  The best video I could get, however, was from the normal view we see on television (only quick looks from other angles).  That side view meant that I could determine the component of Manning’s velocity parallel to the sideline, but not perpendicular to it.  Click here for the article and you will see images I used of Manning in motion.  From the 23-yard line to the 27-yard line, Manning was running mostly parallel to the sideline, but he did drift slightly toward the sideline while running those four yards.  That part of his run represented the best shot I had at seeing Manning running parallel to the sideline, so that my speed calculation could be compared to what the NFL found.  My guess is the NFL used overhead images, which would have been nice to analyse.

To give you a better feel for why it is challenging to determine speed from video, consider the screen capture below (click on the image for a larger view).

You can see the NFL’s speedometer showing Manning running at 17 mph.  There is, of course, error associated with that number.  What I really want you to see is the orange arrow I put on Manning.  That shows approximately the direction of his velocity vector as he ran past the 21-yard line.  My modelling of the run, therefore, began after he squared his shoulders and got moving more parallel to the sideline.

I found a maximum speed of a little more than 16 mph (26 kph), and I estimated an error of no more than 10%.  Given what I had to work with, I would say the NFL’s speedometer was reasonably accurate.  But as I mentioned above, an overhead view would have allowed me to determine his velocity vector instead of just the component of that vector parallel to the sideline.

Manning is listed at 6′ 5″ (1.96 m) tall and he’s been a great athlete most of his life.  Athleticism and a long stride length help with speed (just ask Usain Bolt, whose height is about the same as Manning’s).  Still, hitting 16 mph – 17 mph certainly isn’t bad for a guy nearing 40 years old!

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Recalling Challenger

Have 30 years really passed since the Challenger space shuttle exploded?  That time period represents a generation.  I can see that sad Tuesday in my head quite well even now.  I was 15 years old at the time.  My 10th-grade English teacher had wheeled a television into our classroom so that we could watch the launch.  Though shuttle missions had become less of an event since Columbia flew its maiden voyage in 1981, and Challenger was on its 10th mission on that dreadful day in 1986, the Challenger lift off we watched 30 years ago was special because of crew member Christa McAuliffe.  She was to be the first school teacher in space, and my English teacher was giddy with anticipation just before the launch.  It’s why we watched — to see a “regular person” make it into space.

Everyone has seen the awful explosion just 73 seconds after take-off.  I will never forget my English teacher crying after it happened.  I will never forget the feeling that what I had seen was not real.  It took awhile for my 15-year-old mind to realize that I had watched seven people die.  For my parents, “Where were you when JFK was shot?” was a common question.  For people my age, “Where were you when Challenger exploded?” has been a common question.  Other events like 9/11 have followed the “when” in the question.  I remember 28 January 1986 as being one year to the day since We Are The World was recorded.  I remember that Tuesday as being just two days after the Chicago Bears made a strong case in Super Bowl XX for the best football team of all time.  Not long afterwards, I remember seeing Richard Feynman put an O-ring in cold water to demonstrate that the material comprising the O-rings was not suitable for the cold weather of the January launch.  Richard Feynman became a superstar in my 15-year-old nerdy head.

I had to look up the other names of the Challenger crew members because besides McAuliffe, I remembered only Ronald McNair.  He had a PhD in physics from MIT and a black belt in karate.  I have read some of his work on karate physics.  He seemed like a cool guy when I was 15, and even more so now.  The other crew members were Francis Scobee, Michael Smith, Ellison Onizuka, Judith Resnik, and Gregory Jarvis.  I am glad to look up the names today because remembering those who sacrificed their lives for the advancement of science is important.

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Best Hail Mary Ever?

Think of the great Hail Mary passes in American football.  Staubach to Pearson at the end of ’75 got the term into our vernacular.  My favorite Hail Mary was in ’84 when Flutie hit Phelan to beat Miami in the Orange Bowl.  Not only was that a great game, but I was 14 years old, meaning great things happening in my life at that time would undoubtedly stand out in my mind for the rest of my life.  I loved the play so much that I devoted a chapter to it in my first book.  I saw a Hail Mary this past weekend that will rival Flutie’s pass when the great Hail Mary passes are ranked again.

On Saturday night, 16 January 2016, the Green Bay Packers were trailing the Arizona Cardinals, 13-20, in an NFC division play-off game.  With just 5 s on the game clock, the Packers had one play left, but they were on the Arizona 41-yard line, and they needed a touchdown to force overtime.  I grabbed the screen image below just before the snap (click on the image for a larger view).

All pertinent information is supplied by NBC in the screen shot.  Aaron Rogers took the snap from the shotgun formation, and Arizona brought pressure.  Rogers stepped back and scrambled to his left.  It took 4.2 s for him to release his pass after the snap (click on the image for a larger view).

Look at that throw!  Rogers had a man in his face while falling back to his left as he threw.  I grabbed the screen image below from instant replay (click on the image for a larger view).

Pure athleticism and talent helped Rogers release the ball with a spiral.  You will note that he released the ball about 5.5 yards inside his own territory and well left of the left hash marks.  After spending 3.6 s in the air, Jeff Janis snagged the ball about 5 yards past the goal line (click on the image for a larger view).

I estimated that the ball travelled horizontally almost 61 yards (56 m).  Taking into account air resistance, but no wind (I do not know the weather conditions at the time of the pass), I calculated that Rogers released the pass at 56.4 mph (25.2 m/s or 90.7 kph) and 46.9 degrees above the horizontal.  Just after Rogers let go of the ball, the ball experienced a drag force from the air that was almost 22% of its weight.  Janis, who certainly deserves credit for an amazing catch, one that had to be reviewed to ensure he had possession throughout his fall to the turf, caught the ball travelling 49.0 mph (21.9 m/s or 78.8 kph).  The plot below shows the trajectory (click on the image for a larger view).

The maximum height of the ball was nearly 20 yards (18 m) above the turf.  That vertical distance represents two first downs!

After such an amazing play put the game into overtime, a coin flip fiasco gave the Cardinals first possession in overtime.  Their first play was a Palmer-to-Fitzgerald pass for 75 yards.  Two plays later, Fitzgerald caught the winning touchdown pass from Palmer.  Despite the loss, Aaron Rogers threw what has to be one of the greatest Hail Mary passes of all time.

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A Day in Nottingham

My family took advantage of a beautiful day (clear skies and 0 C) this past Saturday (16 January) by hopping on a train for Nottingham.  When we were here seven years ago, we visited Sherwood Forest, but did not make it into the city of Nottingham.  We discovered on Saturday that Nottingham has a lot of offer!

Our first stop was the City of Caves.  We learned from a great guide that Nottingham has something like 500 caves below it.  Some of the caves we toured are beneath the Broadmarsh shopping centre.   I like the room in the photo below (click on the image for a larger view).

This horseshoe-shaped room stored beer for a pub called the Three Horseshoes (was this cellar the fourth horseshoe?).  A hole in the ceiling was used to warn gamblers in the room that local authorities were about to raid the pub.  The room off to the left in the above photo was dug out during World War II as a place to store documents in case the Germans made their way into England.  We also saw an air-raid shelter from World War II, though Nottingham was not hit like other cities in England.  Not far from the pub cellar are the medieval tanneries.  All fascinating to see and hear about!

We next visited Nottingham Castle, which dates to the 11th century.  But before entering the castle, I just had to pose with the Robin Hood statue (click on the image for a larger view).

My bloody left ulna is still broken, so I could not come close to holding a pulled bow like the folk legend in the statue.  Once in the castle, we especially enjoyed the view of Nottingham just outside the Ducal Mansion (click on the image for a larger view).

Nottingham Station, where we got the train, is visible left of centre behind the “British Waterways” building.  The station has a nice clock on top.

After a great day of learning about Nottingham, we were met with snow when we arrived back in Sheffield.  The city looked beautiful at night with snow on it.  Not a bad way to end a great day!

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Winter Holiday in Norway

My daughters had a fortnight-long winter break from their respective Sheffield schools.  We took advantage of their break and spent ten days in Norway (21 December – 30 December).  What a beautiful country!  Most people we encountered were very friendly, almost all spoke English quite well, and public transportation made getting around easy.

We spent six days in Oslo.  That is one clean city, probably the cleanest city I’ve visited.    Even the subway stations are immaculate.  In late December at approximately 60 degrees latitude, there are only about six hours between sunrise and sunset, so we had to make the most of the daylight.  We visited a Christmas market (click on image for a larger view).

We enjoyed great food, including wonderfully-prepared fresh fish and traditional Norwegian fare on Christmas Eve.  One of many new experiences for me was ice skating on an outdoor rink (click on the image for a larger view).

Not bad form for a nerdy physicist, huh?  Well, perhaps I could use more practice!  I’ve not ice skated much in my life, but I’ve got more appreciation for those who zoom on the ice, be they figure skaters or ice-hockey players.  We toured the Oslo Harbour and walked many streets.  Part of Boxing Day was spent at Frogner Park.  The photo below shows the monolith, one of many cool statues in the park (click in the image for a larger view).

Boxing Day in 2015 will remain in my memory for a long, long time.  When I first learned that my family would return to Sheffield for my second sabbatical, I had the idea of spending Christmas in Norway.  Not only have I always wanted to visit Norway, I wanted to be in snow during the Christmas holiday.  For about a year, my family has been anticipating skiing in Norway.  Boxing Day was our last full day in Oslo; we were headed to the ski resort at Hemsedal on the following day.  I took my daughters to a playground near the home we were renting.  I’ve been studying friction between shoes and sports surfaces since my sabbatical research commenced.  I wish I had just a bit more friction on Boxing Day because I slipped at the playground and broke my left ulna.  No skiing for me!

So after a year looking forward to skiing in Norway, I had to sit on the sidelines and watch my wife and daughters hit the slopes.  But accidents happen, and there are definitely no do-overs in life.  Accepting reality is sometimes easier said than done.  As much as I hated missing out on skiing, I would have felt ten times worse had my wife or one of my daughters been the one sitting in the lodge.  I’m glad they had fun!

I still enjoyed Hemsedal.  It was a winter wonderland.  I witnessed beauty in nature almost everywhere I looked.  My family did some dogsled riding while there.  I was unable to drive, but thoroughly enjoyed the ride.  The scenery was breathtaking (click on the image for a larger view).

I learned a great deal about how the dogsleds work, what the dogs are like, and got some great ideas for physics problems.

It was tough leaving Hemsedal, knowing that I did not get to ski, and wondering if I would make it back at some point in the future.  The photo below shows my last look at the ski resort (click on the image for a larger view).

Beautiful, isn’t it?  Despite my broken arm, I loved being in Norway over the holidays.  Sometimes life doesn’t go exactly like you want it to go.  What’s important is making the best of life, not only for yourself, but for those around you.  We get one shot at life.  Make the most of each and every day!

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Look Ahead to Stephen Curry in 2016

My family was in Oslo, Norway on Christmas Eve.  We stopped in a newsstand near the Oslo Harbour and picked up the latest issue of TIME Magazine.  Adele is on the cover of the special double issue called “The Year Ahead.”  I contributed to the story on Stephen Curry called “Stephen Curry and the Greatest Show on Earth.”  Click here if you have a TIME subscription and wish to read the article.  As I did for the Wall Street Journal last December (click here for that article), I analyzed Curry’s shooting motion and the trajectories of several of his shots.  The guy is amazing!  He has an incredibly quick release that produces high-angle trajectories into the basket.  I like that TIME included my observation that Curry was born on Pi Day!

Happy New Year!

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UK Petrol Passes Below £1 per Litre

I was watching the BBC at Ponds Forge this morning while I was pedalling away on a recumbent bike.  One report noted that the price of petrol sold by a company is now slightly less than £1 per litre (click here for the story).  It got me wondering what that translates into dollars per gallon, which is more familiar to me.  One litre is approximately 0.2642 US liquid gallons, or one could state that one US liquid gallon is roughly 3.785 litres.  Thus if it takes £1 to purchase one litre of petrol here in the UK, it costs about £3.785 to buy one US liquid gallon of petrol.  Hopping on Google’s “pounds to dollars” converter for today, £3.785 is equivalent to $5.73.

The price of petrol in the UK is considerably more than what people pay in the US.  The average cost today for a gallon of regular unleaded in the US is $2.012 (click here for my source, but note that the number changes daily).  People in the UK thus pay about 2.85 times for petrol what people in the US pay.
There was some hype about petrol prices falling below £1 per litre, and I’m sure there will be many happy customers at the pump.  But excitement is relative.  It’s good to keep an eye on what happens outside one’s country, of course, even the stuff that doesn’t make huge headlines.
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Derrick Henry and Football Physics

Rain greeted me this morning on my way to the gym, but as I wrote yesterday, that is nothing new.  Back in the US, college football fans are gearing up for bowl season.  But before those games will be played a certain famous trophy must be presented.  One talented young man will have his life forever changed when he accepts the Heisman Trophy this Saturday night.  I’ll try to stay up for the announcement, but it will be early Sunday morning for me when the winner’s name is called.

Three deserving finalists will be in New York for the Heisman ceremony.  Strong and convincing cases can easily be made for Christian McCaffrey of Stanford and Deshaun Watson of Clemson.  But my money is on Derrick Henry of Alabama to become the Crimson Tide’s second Heisman winner.  I could certainly be wrong, but as someone who did his undergraduate work in the Southeastern Conference, my rooting interest is with the Alabama running back.

I recently got to study game film of Derrick Henry in preparation for a story the Alabama Media Group was putting together on the science behind Henry’s dominance.  At 6′ 3″ (1.905 m), Henry is quite tall for a running back.  Usually the guys who run the ball have a center of gravity that isn’t so far off the ground.  But I learned a few things watching Henry in action.  Click here for the article that contains some of my physics analysis of Henry’s running.  That guy will be playing on Sundays someday!

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Wet and Windy in England

I’ve been slow to keep up my blog writing, especially as it pertains to my sabbatical experiences.  Late 2015 here in South Yorkshire has seen lots of wind and rain.  We have rarely found a day in the past month that we’ve not felt at least a little mist on our faces.  People north of us have had it much worse with Storm Desmond causing lots of flood damage.  For all the rain and wind, it’s great being in Sheffield as holiday time approaches.  The city centre is decorated and fun to see at night when I’m on a bus headed for home after work. With the sun setting before 4 pm now, it’s always night when I leave work!

A torn muscle in my left calf has kept us from doing much travelling of late.  Before the tear, my girls and I toured Shepherd Wheel, which is quite close to where we live.  Kudos to the woman (a volunteer?) we met there because she gave us lots of great information.  The wheel makes use of water that’s been dammed from the Porter Brook.  I took the photo below on Sunday, 15 November 2015 (click on the image for a larger view).

The wheel is 18 ft (5.5 m) in diameter.  The large shaft through the wheel sends lots of kinetic energy into the building that’s used for various grinding work.  It’s great watching energy conversions in action!

Walking to Shepherd Wheel took us through Endcliffe Park, which is our wonderful local park.  The photo below shows the Porter Brook in Endcliffe Park, downstream from the Shepherd Wheel (click on the image for a larger view).

Wet weather could not distract from the natural beauty in the park.

This past Sunday, which was 6 December 2015, my family visited the 23rd Victorian Christmas Market at Kelham Island Museum.  That was a lot of fun!  We saw people dressed as Dickens characters, heard great bagpipe music and Christmas songs, and visited many shopping stalls.  I couldn’t resist getting a fine pint while I was there and a jar of lemon curd to take home.  My younger daughter snapped the photo below of some reindeer at the market (click on the image for a larger view).

Some of the fine singers we heard are seen in the photo below (click on the image for a larger view).

It was a fun day to be out with family and denizens of Sheffield as we enjoyed a little holiday cheer.

Sabbatical research continues to stimulate my mind and keep me busy.  As a clumsy theoretical physicist who is more comfortable writing code and using a pencil and paper than tinkering in a lab, I am continually amazed by the ingenuity of people with experimental and engineering training.  Lots of what we do on a piece of paper takes for granted just how hard it is to build and measure what we’re scribbling on that paper.  I take great joy in seeing what clever people construct to allow for precise measurements.

I am also enjoying the one hour per week I get to teach.  I volunteered to teach one of the second-year tutorials for the physics department.  My eight students are great and I enjoy interacting with them each week.  They see an enormous amount of material, so much that I wonder if being exposed to that much material is truly effective.  Just two days ago, I talked to my students about Lagrange’s equations in mechanics, non-inertial forces, the infinite square well in quantum mechanics, and Born’s interpretations of the wave function.  It’s out of this world fun for me because I can yap about many areas of physics, but it’s a lot for my students to digest.

Holiday break commences on Saturday, 19 December 2015.  Lots of research work to do before then!

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A Little Boxing Science

I contributed to an article in the current issue of The Ring, known as The Bible of Boxing.  What’s funny is that the December 2015 issue has been out in the US for some time now.  I’ve been checking in at WH Smith on Fargate for over a week.  After a good workout at Ponds Forge this morning, I nipped into WH Smith — and they finally had it!

Keith Idec is the reporter I worked with.  He wrote nice article called “Balance of Power,” in which he describes how big boxers combine intrinsic talent with skill developed over years of training to produce some pretty powerful punches.  I contributed to the section “Properties of Power” on page 63.  A few more of my comments appear on pages 64-65.

It was a lot of fun working on the piece.  The human body is capable of delivering enormous amounts of power over short time intervals.  Tour de France cyclists can briefly output over a kilowatt.  Boxers can surely do that over a the brief time of a monster punch.  There is no way I would want to be on the receiving end of one of those punches!

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